DE1911423A1 - Mixtures of substances containing metal flakes - Google Patents

Description

PATENT LAWYERS

DR.-ING. BY KREISLER DR.-iNG. SCHDNWALD DR.-ING. TH. MEYER DR. FUES D! PL.-CHEM. ALEK VON KREISLER DiPL.-CHEM. CAROLA KELLER DR.-ING. KLDPSCH

COLOGNE 1, DEICHMANNHAUS

Cologne, March 4th, 1969 Fu / Ax / Hz

The British Petroleum Company Limited, Britannic House, Moor Lane, London, E.C. 2 (England).

Mixtures of substances containing metal flakes

The invention "relates to oil mixtures, the metal flakes contain, especially liquids in which metal flakes are dispersed.

Processes for the production of tietallflocken are in the

German patents (patent application

P 16 07 4-54.7) and. (Patent application P

corresponding to the applicant's British patent application 6108/68). It has now been found that Mixtures of substances that contain metal flakes which, according to the ■ Process of the aforementioned patents can be produced and have a high surface energy, a large one With a surface and a low bulk density, they have many valuable properties.

The invention relates to mixtures of substances that have a liquid Dispersing medium and metal flakes dispersed therein, which have a surface energy of little

at least 0.01 cal / g, a surface area of at least 1 m / g and a bulk density of less than 1 g / cmr .

The metal flakes suitable for the purposes of the invention can be produced by placing a metal in a

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organic liquid (hereinafter referred to as organic cooling liquid referred to) in the presence of a grinding aid, e.g. a high pressure or high pressure additive for lubricants, is milled · Preferably one with a high Energy-working mill, e.g. a vibrating ball mill with an oscillation amplitude of at least 2 mm and an oscillation frequency of at least 500 / minute are used. ~

Suitable organic liquids are, for example, hydrocarbons, in particular n-heptane, isooctane, cyclohexane, toluene, hexadecane and hydrocarbon fractions obtained by distilling petroleum. Other suitable liquids are most volatile liquids containing oxygen, halogen, nitrogen and sulfur. The milling liquids preferably have a surface tension of less than 72 dynes / cm, in particular of less than 4-5 dynes / cm at 25 ° C. The viscosity of the liquid at the grinding temperature must be so low that the grinding process can proceed with sufficient energy so that a metal powder with the desired surface energy, surface area and the desired bulk density is formed. For this reason, preferably liquids are used which have a viscosity of less than 30 cS, have in particular less than 3 cS at 38 ⁰ C, with a viscosity of less than 1 cS is particularly be.vorzugt.

A "grinding aid" is understood to mean a compound that makes grinding easier. For this purpose, high pressure and maximum pressure additives are used for lubricants, fatty acids, Fatty acid esters and fatty alcohols are used.

The coolant can be any usual load-bearing capacity and contain load-bearing additives for lubricants. These high pressure and extreme pressure additives are usually compounds that contain one or more elements of groups 5 »6 or 7 of the periodic table, especially nitrogen, phosphorus, sulfur and chlorine

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contain. The grinding liquids can be used as grinding aid also a fatty alcohol, a fatty acid or its ester either in addition to the high pressure or extreme pressure additive or included in its place. In general it is Additive or acid, the more effective the grinding process, the better the lubricating effect of the additive or the Acid is on the unground ketal. Preferred as additives to increase the load-bearing capacity and the pressure absorption capacity becomes carbon tetrachloride, and preferred fatty acids are stearic acid, palmitic acid or their vinyl esters. Getyl alcohol can also be used.

As!. 'Metals come, in the context of the invention the transition metals, in particular iron, aluminum, copper, zinc, tin and lead. Alloys, ζ.3. Cast iron, steel and Brass, can also be used.

Milling is preferably done with practical exclusion carried out by air. Preferably, the metal is located below the surface of the milling liquid during milling.

The metal flakes used for the purposes of the invention preferably have a surface energy of at least

2 0.05 cal / g, a surface area of at least 2 m / g and a Debris weight less than 0.5 g / cm. In certain cases surface energies of more than 10 cal / g to 100 cal / g can be achieved.

The surface energy of the metal flakes can be made using of the flow microcalorimeter, which is described in "Chemistry and Industry" of March 20, 1965, pages 4-82 to 4-89 using n-butanol which adsorbs from n-heptane will be determined.

The high surface energy of the for the purposes of the invention metal flakes used allows the formation of stable dispersions in liquids that last a long time

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Service life "with little settling of the metal flakes.

Hydrocarbons, mineral oils or synthetic oils, liquid silicones or any other liquids that do not react with the metal flakes are used as the dispersing medium. - _v

The amount of metal dispersed in the liquid depends on the use for which the dispersion is intended, however, it is preferably 1 to 30% by weight. However, if the liquid is a lubricating oil, a fat is formed, when a sufficient amount of the metal flake is dispersed in the oil will. Typically, 10 to 25% by weight of the high surface energy metal flakes are used in a mineral oil or synthetic base oil to make greases dispersed.

Mineral oils or synthetic oils can be used as base oils will. Refined mineral oils obtained from petroleum, for example those with a viscosity in the range from 2 to 50 cS, preferably from 4 to 40 cS, are suitable as mineral oils at 99 ° C. ■ /;

Organic esters, for example, are suitable as synthetic oils, Polyglycol ethers, polyphenyl ethers, fluorinated hydrocarbons, silicate esters. Silicone oils and their mixtures

The most important class of synthetic oils are the organ! - " see liquid polyesters, especially the neutral polyesters, which have a viscosity in the range from 1 to JO cS 99 ° C. The term "polyester" denotes esters that have at least 2 ester bonds per molecule. The expression "neutral" serves on? Designation of a complete ■ esterified product. Suitable polyesters are, for example liquid diesters of aliphatic dicarboxylic acids and monohydric alcohols (e.g. dioctyl sebacate, dinonyl sebacate, octyl nonyl sebacate and the corresponding Az © lat @ and adipates), liquid diesters of aliphatic dicarboxylic acids and phenols (e.g. those described in the British patent

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Writings 1 059 955, 1 058 906, 1 044 550 and 1 044 883 and

in the German patent specification (patent application

P 15 94 35O.7) "described by the applicant) and more complex Polyesters (e.g. those described in British Patents 666 697, 7 ^ 3 571, 780 034, 861 962, 933 721, 971 901 and

986 068 and in German patents

(Patent application P I5 94 343.8) and ......... (patent application P 15 94 35O.7) described by the applicant).

The fine metal powders can be incorporated into the fats by various methods. "Preferably the Incorporation of the fine metal powder into a fat immediately after grinding. However, if the fine metal powder some time before adding to the fat, it is preferably stored in an airtight container "in order to." prevent damage.

The slurry of fine metal powder can, for example can be converted into fat as follows:

a) The grinding liquid is filtered off. The filter cake obtained is ground in a colloid mill, for example, and the powder obtained is stirred into the oil.

The fat obtained is finished by grinding in the colloid mill.

b) The grinding liquid is quickly evaporated to avoid the formation of a metal powder cake, and the resultant Powder is stirred into the oil and the fat through. Finished grinding in the colloid mill.

c) The oil becomes the slurry of fine metal powder added and the grinding liquid distilled off.

d) the slurry of fine metal powder, the oil is added and the mixture in a homogenizer (for example, _e a Manton-Gaulin homogenizer) treated so that temperatures of up 140 ⁰ G or higher · The temperature must be so high that the milling liquid departed

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is driven.

e) The metal can also be ground directly in the base oil for the fat. For example, a low-boiling, low-viscosity mineral lubricating oil can be used advertising "the having a low surface tension and a viscosity of up to 600 cS at 38 ⁰ C. Las Kahler can be carried out at elevated temperatures up to 400 ⁰ O '

Processes c), d) and e) are particularly preferred. In general, the fine metal powders may be in the base oil at ambient temperature or optionally at elevated temperatures, for example ⁰ to 400 C are incorporated.

The fats according to the invention have remarkably high dropping points. If the "drop points are measured according to IP or ASTM standard methods, they are above 400 C _9. These fats are referred to as" infusible "and are difficult to manufacture using conventional methods. By using carefully selected basic oils, eg synthetic oils with a high degree of oxidation »And heat resistance, greases can be made with a unique combination of properties.

In certain circumstances it can be advantageous to use the metal add dispersants before or after grinding. In this way, the fine metal powder can be dispersed accelerated and improved. Furthermore, viscosity index improvers, Metal deactivators, anti-corrosion agents ^ antioxidants etc. can be added.

It has been found that the dispersions according to the invention have high pressure or "maximum pressure properties, and that the Dispersions of metal flakes in lubricating oils, di © Hochdruokbsw. Improve HÖclist seal properties of the oils

Liquids containing ferromagnetic flakes' ha-

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ben properties that differ in some respects from the properties of liquids that are non-ferromagnetic Contain flakes, distinguish. Dispersions of iron flakes in a liquid make up the entire liquid sensitive to magnetic fields. For example, it is possible to make the bulk of the liquid magnetic Forces to move. This also applies to fats thickened with iron flakes. Thickened with iron flakes Fats are also electrically conductive. These properties of dispersions of iron flakes are very beneficial in electrical power plants, transmissions, pumps and non-mechanical valves.

Fats thickened with iron flakes harden in the process Machining in contrast to common greases. The values of the penetration of the fat are thus after fulling less.

The dispersions of other metals in organic liquids * - ten are suitable for electrostatic applications, e.g. in control mechanisms, e.g. valves.

example

Different metals were made into n-heptane, which is different Contained lubricant additives, using a "Megapact" - "mills (manufacturer Pilamec Limited) ground. In this mill, the bald rooms are made of steel cylinders of 38 mm inside diameter and 3½ cm in length. You are with hardened steel balls of 6.35 mm diameter almost filled. The mill is equipped with an electric motor of 1/4 HP. The oscillation can be adjusted from 1 to 4 mm. In operation, each cylinder was completely filled with n-heptane filled, which contains the lubricant additive -was what the steel balls and 10 to 50 g of metal powder, the particles of which passed through a 37-310 Ai sieve, were added. The ends were then with metal caps, which were provided with rubber sealing rings, closed, whereupon at an oscillation amplitude of

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4 mm and an oscillation frequency of 3000 / minute ground became. Each time the grinding was done, the balls were made from the slurry Sieved from the metal powder, the n-heptane and lubricant additive, whereupon the treated metal powder through "Filtration, washing and drying were separated *

The metal powders were in a mineral green oil .160 / 95, stirred in, forming a fat that was 25 wt .-? 6 of the metal contained. The base oil had a viscosity of 160 Redwood Rr. 1 seconds at 60 0 and a viscosity index of 95 · The properties of these fats are in given in the following table:

metal stole aluminum Grind additive Stearic acid Falmitic acid Amount of mill additive, wt. -% 5 5 Surface energy, cal / g * 106 0.12 Surface, m / g 18th 1 Bulk weight, g / cnr 0.19 0.19 vYalkpenetration, 60 shocks 223 324 Resting penetration 290 298

* ./ Heat of interaction of n-butanol, measured without removal the adsorbed grinding liquid.

The fat formed with the steel flakes had a specific one Resistance of 45 ohms / cm. If this fat in a Magnetic field was applied, it hardened and became rigid.

Dispersions were prepared by dispersing the metal flakes in n-heptane and allowing them to stand still for 24 hours. The suspensions were black and contained 5 wt -.% Of the flakes. After this time, flake settling was observed.

when the suspension containing the iron flakes in-one When a magnetic field was applied, the total mass of the liquid was affected and its shape changed in response to the magnetic field. A separation of the iron flakes

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under the influence of the magnetic field did not take place.

It is very surprising that the metal flakes the oils too Fats thicken and that the liquids that contain the iron flakes are opposed through their entire mass Magnetic fields can be made sensitive.

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Claims (1)

191H23 - Io - Claims In that it contains dispersed in a liquid dispersion medium, metal flakes I ^ metallic flake containing mixture, characterized in that cnr a surface energy of at least o, oil cal / g, a surface area of at least 1 rn / g and a bulk density of less than 1 g / to have. Mixture of substances according to claim 1, characterized in that that the metal flakes have a surface energy of at least 0.05 cal / g. j5. Mixture of substances according to Claims 1 and 2, characterized in that that the metal flakes have a surface area of at least 2 m / g. 4; Mixture of substances according to Claims 1 to 3 *, characterized in that the metal flakes have ^{a bulk density of less than 0.5 g / cm 5.} 5. Mixture of substances according to Claims 1 to 4, characterized in that the metal flakes are produced by grinding the. Metal in an organic liquid with a surface tension of less than 72 dynes / cm at 25 ⁰ C, a viscosity of less than 3o cS at 38 ⁰ C in the presence of a grinding aid in a vibration ball mill , the metal preferably practically during the The entire grinding process has been kept below the surface of the liquid and in particular grinding liquids have been used whose surface tension is below 45 dyn / om and whose viscosity is less than 1 ½, in particular less than 1 ½ at 38 ^° C. 909 88 5 / U07 ; Γ; ί - ιι - 6. otofigeniisch according to claims 1 to 5> by 'üaß the Metällflocken by grinding in a liquid hydrocarbon, for example a Parafrin have been _prepared: 7. S to ff semi ε ch ■ according to claims 1 .to 6, characterized in that that grinding in the presence of an additive which improves the pressure absorption capacity containing nitrogen, phosphorus, chlorine and / or sulfur has been carried out, wherein :. especially as such an auxiliary agent, carbon tetrachloride has been used. 8. Mixture of substances according to Claims 1 to 6, characterized in that that the metal flakes in the presence of fatty acids, .. Fettäurestern.oder fatty alcohols as Grinding aids have been produced, preferably with Stearic acid, palmitic acid, yinyl stearate, Vinyl paliritate or cetyl alcohol has been used " - .., - ■ are. . . ... 9. Mixture of substances according to claims 1 to S, thereby ge ■ indicates that the liquid dispersing medium is a mineral lubricating oil or a synthetic Sohir. - ■ _ oil is .. lo. Material geiaisch according to claims 1 to 9, characterized. ■ indicates that _r 1 - is pe .. wt -ft contains metal flakes, ..wobei preferably the content of metal flakes ... dimensioned such .. that a Schmierfettbeschaf- ■;. ■ ·, - fenheit. trains and. especially the metal ...>. -flock gasshalt. Io - 25 Gev: .- <$ matters ". 9 O 9 8 8 B7 ¹ L O ^η 19.1H23 11. Mixture of substances according to Claims 1 to 8, characterized in that that the liquid dispersing medium is a hydrocarbon. 12. Mixture of substances according to Claims 1 to 11, characterized in that the metal flakes are a transition metal. Aluminum, copper, zinc, tin, or lead, or alloys of these metals, are v / obei that Metal can be in particular iron or an iron alloy. 9 0 9 8 8 «? / -1 L 0 7