EP0593651B1 - Lubrification composition, method for preparing same, and uses thereof, particularly as an additive for oils - Google Patents

Abstract

PCT No. PCT/FR92/00641 Sec. 371 Date Apr. 20, 1994 Sec. 102(e) Date Apr. 20, 1994 PCT Filed Jul. 6, 1992 PCT Pub. No. WO93/01262 PCT Pub. Date Jan. 21, 1993.A substantially anhydrous lubricating composition containing solid particles of a fluorinated (co)polymer having a maximum size of 1 mu m and coated with an ethoxylated nonylphenol having 10-12 ethylene oxide molecules. A preparation method is also provided.

Description

This request concerns a composition lubricant, its preparation process and its applications, especially as an additive in oils.

Base oils produced by companies for use as lubricants are monograde oils. Most engines such as internal combustion, petrol or diesel engines for automobiles by example, use multigrade oils.

Additives must be incorporated into these oils monogrades to obtain multigrade oils after mixing.

These insoluble or immiscible additives to oils are subject to sulfonation reactions to be dissolved in the oils to which they are added. With aging, oils release acids which corrode motors, especially motors stationary.

To avoid corrosion of the motors, more particularly stationary motors, so it's necessary to increase oil changes or protect the metal surfaces against acid corrosion.

Furthermore, when the engines remain unused for a certain period, many parts metal dry out completely that there is no more lubricating fluid film between metal parts usually in motion and they are no longer at all lubricated at the start of engine start-up and during some time ; a metal-metal contact is then established.

It would therefore be desirable to develop an oil lubrication preventing drying of these metal surfaces or at least allow the recovery of the parts metallic by a layer of solid lubricant making lubricant office at the start of engine start-up. Such a solid lubricant should also be attached to the all metal surfaces to be greased.

French patent application No. 2,359,200 describes a hybrid lubricant dilutable in a lubricating oil conventional fluid, comprising a colloidal aqueous dispersion of polytetrafluoroethylene particles, an agent neutralizing and stabilizing, a fluid lubricating oil carrier incorporated into the stabilized dispersion to form with it an emulsion, which emulsion contains an agent dispersing agent and finally a wetting agent added to the emulsion endowed with affinity for rubbing surfaces so as to predispose them to be impregnated with said particles and merge with them to form a lubricating layer superficial.

However, the hybrid lubricant uses a aqueous dispersion. However, the presence of water harms the effect of lubrication of oils, especially at high temperatures where it is vaporized, causing circulation difficulties in his circuit.

European patent No. 0 293 427 relates to a process for making a dispersion of polytetrafluoroethylene as a lubricating oil or additive to this last. In this process, a non-surface active agent is fixed. ionic to polytetrafluoroethylene particles thanks to a heat treatment in several temperature zones decreasing including a first zone with very high temperature high, detrimental to the quality of the oil.

It would be desirable to have a composition lubricant for use as a lubricating oil or the latter in which particles of (co) polymer fluorinated would be perfectly miscible with the fluid in which they would be in stable suspension, without changing their basic characteristics, without fear of release or settling of said particles in the fluid.

This is why the subject of this request is a lubricating composition, characterized in that it contains solid particles of fluorinated (co) polymer of size less than or equal to 1 µm covered with a nonylphenol ethoxylated with 10 to 12 molecules of ethylene oxide and what it is substantially anhydrous.

Preferred compositions according to the invention are compositions characterized in that the particles of (co) fluoropolymer are covered with a saturating amount stable of ethoxylated nonylphenol.

Among the compositions according to the invention, preferably retain those in which the (co) polymer fluorinated is polytetrafluoroethylene, as well as those in which ethoxylated nonylphenol contains 11 molecules ethoxyl. In other preferential conditions, the weight ratio of ethoxylated nonylphenol to fluorinated polymer is about 2 to 1 in the case of polytetrafluoroethylene, and ethoxylated nonylphenol with 11 ethoxyl molecules.

The present invention also relates to a lubricant characterized in that it contains a composition lubricant as defined above.

The present request also relates to a process for preparing a lubricating composition containing particles of fluorinated (co) polymer in suspension characterized in that particles of the (co) polymer are treated substantially anhydrous fluoride of smaller size or equal to 1 µm using a volume substantially double one ethoxylated nonylphenol with 10, 11 or 12 ethoxyl molecules itself also substantially anhydrous, with stirring and anhydrous atmosphere, to obtain the lubricating composition expected.

The fluorinated (co) polymer can be a fluorinated resin chosen from fluorinated polymers and copolymers, perfluoroalkoxylated (co) polymers, partially fluorinated (preferably perhalogenated) (co) polymers. These (co) polymers can be used alone or as a mixture. Mention may in particular be made of Teflon ^R (PTFE) essentially composed of tetrafluoroethylene. Mention may also be made of Teflon FEP ^R , a tetrafluoroethylene hexafluoropropylene copolymer. Mention may also be made of Teflon PRPFA _R, which is a perfluorinated alkoxylated polymer. PTFE is preferred, however.

Particles of fluorinated polymer or (co) polymer must be small, i.e. less than 2 µm, and preferably less than or equal to 1 µm. The particles must be substantially anhydrous to know that their humidity must be less than 1%, especially lower to 0.5% and advantageously less than 0.2%.

Particles can be rendered substantially anhydrous by wearing them for a while, by example 24 hours and preferably about 48 hours or more, above room temperature, for example 10 ° C at above it.

The particles used have a density apparent of about 0.5 preferably.

The ethoxylated nonylphenol used is also substantially anhydrous. This anhydrous character can be imparted by heat treatment such as that described above for fluorinated (co) polymer particles. The bulk density of the hydrolyzant is about 1.04.

The fluorinated (co) polymer is mixed with stirring ethoxylated nonylphenol. We implement advantageously approximately 1.7 volumes of ethoxylated nonylphenol per 1 volume of (co) fluorinated polymer. Agitation is preferably carried out in a centrifugal Vortex agitator, advantageously comprising a two-stage turbine and central bias.

The diameter of the turbine is preferably third of that of the tank. Tangential speed at the circumference of the turbine is preferably 15 to 30 m / s and advantageously from 20 to 24 m / s.

The radial axis of the turbine is advantageously located approximately a quarter of the bottom of the total height liquid.

However, any operational condition allowing for particles to achieve 3 to 5 and preferably 4 revolutions per minute can be used.

When adding the fluorinated (co) polymer to the ethoxylated nonylphenol, this operation is preferably performed regularly and quickly. For example for a total weight of fluorinated (co) polymer and ethoxylated nonylphenol weighing 500 kg, the fluorinated (co) polymer is added in two minutes at a regular rate. The agitation of the mixture can be maintained from 30 minutes to an hour and preferably from 35 to 45 minutes, especially around 40 minutes.

The product obtained at the end of the process has the appearance a thick thixotropic and adherent paste which can by example be lengthened with about 15% oil basic mineral, neutral, monograde. This composition elongated can be transferred.

The transferable composition is miscible in lubricating oil. The composition is not soluble in oils and therefore has the advantage of keeping lubricating oils their original properties without modification by adding his own. The transferable solution can be mixed in the lubricating oil intended for petrol, diesel, two-stroke engines, hydraulic, mechanical or automatic transmissions or still to reducers, etc .... The composition according to the present invention is particularly effective in the case oils circulating in a circuit.

For its use as a lubricant, the dosage usable is about 8 grams per liter of a composition transferable elongated as indicated above (by 15% mineral oil).

Applications include the following:

First of all we carry out a pre-dosage which consists in mixing with a quantity of oil the composition transferable. For example, in the case of use in situ, 15 grams of composition transferable into solution in 0.8 liters of oil can be added to 5 liters quality oil conforming to that recommended by a car manufacturer for example.

You can also incorporate the dough into a fat thick thixotropic obtained by the implementation of process (without incorporation of mineral oil). The fat thus modified has the advantage, as in the case of engines or transmissions, after prolonged immobilization, avoid the inconvenience of dry contact between metals. he the same is true for plain bearings, especially due to the low contact surfaces, for ball bearings, with rollers on which, during starts, we avoid specialists' dreaded metal pull-outs.

Thanks to the implementation of the composition lubricant according to the invention in an internal combustion engine, the gradually becomes more flexible as and as the treatment produces its effects. The start becomes easier, engine wear is slowed down, some standards are restored, in particular the rates of compression balance and return to normal, and segments possibly glued by the residues peel off and again fulfill their sealing and stoichiometric stability, preventing oil from rising in combustion chambers and fuel splashes in oil.

Thanks to the adapted particle size of fluorinated (co) polymer, in particular of the polytetrafluoroethylene type, these easily pass through the oil filter without clogging.

Finally the contents of unburned hydrocarbons and carbon oxides, especially carbon monoxide are reduced, thereby reducing air pollution.

EXAMPLE 1:

Regularly poured in two minutes into the center of the turbine 333 Kg of micronized polytetrafluoroethylene whose particle size is of the order of 6.5 μm sold by the company ICI under the reference F170 and stored beforehand for 48 hours at the temperature of 30 ° C, in 660 kg of nonylphenol ethoxylated with 11 molecules of ethylene oxide marketed by the company Sidobre Sinova under the reference OP 11 also brought to the temperature of 30 ° C for 40 minutes stirred in a mixer of Vortex type centrifugal under the following conditions:
the diameter of the turbine represents approximately one third of the diameter of the tank, the turbine is located at half the height of the ethoxylated nonylphenol, the tangential speed at the periphery of the turbine being adjusted to approximately 22 m / s and the height of the turbine being such that each particle makes about 4 revolutions per minute.

Agitation is continued for 40 minutes at a temperature of 30 ° C and obtains the lubricating composition expected.

In the composition obtained, the particles of polytetrafluoroethylene have a size less than or equal to 1 µm, these particles are miscible in all proportions both commercial multigrade oils and oils monogrades. The composition no longer contains substantially free ethoxylated nonylphenol, i.e. less than 0.1%

The final density of polytetrafluoroethylene particles is about 0.82 versus 0.5 for particles original polytetrafluoroethylene.

The density of the particles being extremely close to that of multigrade commercial oils, these can remain in stable suspension for very long periods extended over time.

EXAMPLE 2: Composition transvasable

The above composition is diluted with 15% basic monograde mineral oil, SAE 30 to obtain a transferable composition.

EXAMPLE 3 Transferable composition

The above composition is diluted with 15% basic monograde mineral oil, SAE 30 to obtain a transferable composition.

Claims (12)

1. Lubricating composition, characterized in that it contains solid particles of fluorinated (co)polymer of a size less than an equal to 1 µm coated with an ethoxylated nonylphenol having 10 to 12 ethylene oxide molecules and in that it is substantially anhydrous.
2. Composition according to claim 1, characterized in that the particles of fluorinated (co)polymer are coated with a stable saturating quantity of ethoxylated nonylphenol.
3. Composition according to claim 1 or 2, characterized in that the fluorinated (co)polymer is polytetrafluoroethylene.
4. Composition according to claim 1 or 2, characterized in that the ethoxylated nonylphenol comprises 10 molecules of ethoxyl.
5. Composition according to one of claims 1 to 3, characterized in that the ratio by weight of ethoxylated nonylphenol to fluorinated polymer is approximately 2 to 1 in the case of polytetrafluoroethylene, and of ethoxylated nonylphenol with 11 ethoxyl molecules.
6. Lubricant characterized in that it contains a lubricating oil or grease, and a lubricating composition as defined in one of claims 1 to 5.
7. Process for preparing a lubricating composition containing particles of fluorinated (co)polymer in suspension characterized in that substantially anhydrous particles of the fluorinated (co)polymer of a size less than or equal to 1 µm are treated with the help of an approximately double volume of an ethoxylated nonylphenol with 10, 11 or 12 molecules of ethoxy itself likewise substantially anhydrous, under stirring and anhydrous atmosphere, in order to obtain the expected lubricating composition.
8. Process according to claim 7, characterized in that the fluorinated (co)polymer is polytetrafluoroethylene.
9. Process according to claim 7 or 8, characterized in that the fluorinated (co)polymer and the ethoxylated nonylphenol are raised to a temperature above the ambient temperature before mixing.
10. Process according to one of claims 7 to 9, characterized in that approximately 1.7 volumes of ethoxylated nonylphenol are used per 1 volume of fluorinated (co)polymer.
11. Process according to one of claims 7 to 10, characterized in that stirring is carried out in a centrifugal vortex stirrer.
12. Process according to claim 11, characterized in that stirring is maintained for approximately 40 minutes for four revolutions of the particles per minute.