RO118969B1 - Grease composition for use at high pressures - Google Patents

Abstract

The invention relates to a grease composition for use at high pressures, applicable to lubricating a wide range of equipments operating in severe temperature duty (-50 ... + 350 C) and pressure (minimum 250 kgf). According to the invention, the grease composition consists of 1 ... 7% amorphous silica or 1 ... 1.5% talc, 9 ... 12% organophilic bentonite, 11 ... 20% mixture of ceresine and basic mineral oil or polytetrafluoroethylene, 60 ... 75% naphthenic mineral and/or paraffine oil, 2.5 ... 5% dimethylcetone, 1 ... 8% polyfunctional additives, 8 ... 28% additive for high pressures, the percentage being expressed by weight.

Description

The invention relates to a greasing composition based on a complex thickener, additive for high pressure resistance, applicable to the lubrication of a wide range of machines operating under severe temperature (-50 ° C + + 350 ° C) and pressure. (minimum

250 kgf).

Lubricant compositions based on a mixed inorganic thickener are known, additives for resistance to high pressures, made from oil obtained from non-paraffinized crude oil, non-additive, for transmissions, with a flash point M minimum 260 ° C, a viscosity index minimum 75 and freezing point maximum 0 ° C, 50.7 ... 80.9% by weight, technical synthesis dimethylketone 1.5 ... 2% by weight, indigenous clay of probe type 12 ... 26% by weight and type bentonite octadecyl-ammonium-bentonite 3 ... 8% by weight (the ratio between thickeners, bentonite and sondafin is 1: 4 ... 1: 3,3), adhesion polymer 1% by weight, additive with anticorrosive role 0,1. ..0.3% by weight and additives for high pressure resistance: 60% molybdenum bisulfide concentrate 3 ... 15% by weight and 30% by weight natural colloidal graphite (RO 112750,112747).

These greases have the following disadvantages:

- does not operate in the low temperature range or higher than 320 ° C;

- ensures a lower resistance of the lubricating film, at high temperatures and pressures;

- it is made on a restrictive basis of clays;

- Probe clay is slightly abrasive.

The technical problem that the invention solves is the elaboration of an additive grease composition with specific additives that have lubrication and resistance properties under conditions of high technical and mechanical demands.

The composition of greases for resistance to high pressures, removes these disadvantages in that it consists of: 1 ... 7% thickening complex of amorphous silica type with a content of minimum silicon dioxide 80% and the particle diameter at an average of 1 pm, or 1 ... 1.5% talc; 9 ... 12% organophilic bentonite with gelling degree 4 ... 69; 11 ... 20% mixture of cherry and basic mineral oil or 11 ... 20% polytetrafluoroethylene type polymer; 60 ... 75% fractions of selected naphthenic and / or paraffinic mineral oils, with values of freezing points -5O ...- 2 ° C; 2.5 ... 5% pure synthetic dimethylketone or dimethylketone solution containing 10 ... 20% calcium; 1 ... 8% polyfunctional additives with anti-corrosive, antioxidant and anti-wear role, having synergistic effect, zinc dialkyl-aryldithiophosphate type or similar effect additives and high pressure additives; 8 ... 28% mixture of synthetic colloidal graphite powder with a carbon content of minimum 99.5% and molybdenum bisulfide powder of minimum 99.5% and 1 +1.5 hardness in the Mohs scale with medium size of particles of 0.6 ... 0.8 pm, or 1 ... 10% additives for high pressures such as synthetic sulfurized esters, sulfurized isobutene, organic compounds with sulfur, phosphorus and / or chlorine, or effect additives similar, the percentages being expressed by weight.

The composition of greases according to the invention has the following advantages:

- ensures the lubrication of the machines in a wide temperature range (-5O ... + 35O ° C);

- has the capacity to withstand high pressures (at least 250 kgf);

- gives lubricated machines a high degree of reliability.

An example of the invention is given below.

in a mixer of 500 kg capacity, provided with a stirring system of type anchors or blades, having double walls (through which water or heating oil circulates) and, on the exhaust system of the mixer, a pump with gear wheels or screws , introduce: 240 kg of mineral oil for refrigeration installations in which it is dosed, at the temperature of 3O ... 4O ° C, 20 kg of probe-like clay and 20 kg of octadecyl-ammonium-bentonite type bentonite, in the presence of dimethylketone 6 kg synthesis technique, homogenizing the mixture formed, for 60 minutes, through the agitation and recirculation system of the pump; raise the temperature to 5O ... 6O ° C, with the product recirculation 4 ... 5 times, to form the grease structure and evaporate the solvent.

RO 118969 Β1

Separately, the preservative additive is formed, consisting of 80 kg of base oil (the one used in the preparation of the grease) in which 33.2 kg of cherry is dispersed, at a temperature of 10 ° C.

After the homogenization of the oil-cherry mixture, the additive with an anticorrosive and antioxidant role, of the benzotriazole type, in the amount of 0.8 kg.

The preservative additive thus obtained is introduced into the mixer at a temperature of 55

9O ... 95 ° C, over the basic grease, is homogenized for about 1 h, by recirculation, with the help of the discharge-charge pump and an amount of 394 kg of preservation grease is obtained, having the following characteristics:

- drip point, ° C = minimum 250;

- colloidal stability (steel, copper and brass) 24 h / 100 ° C = resistance; 60

- neutralization index, mg KOH / g = neutral;

- penetration at 20 ° C, 0.1 mm = 200 ... 295.

The grease based on a complex thickener, adapted for high pressure resistance, according to the invention, has the following basic physico-chemical characteristics:

- drip point, ° C = minimum 280; 65

- degree of consistency = 1 + 4;

- corrosion (3 hours / 100 ° C) on metals (steel, copper, brass, bronze, aluminum) = resistance;

- colloidal stability, separate oil,% = maximum 2;

- high pressure resistance (on 4-ball machine):

a) seamless load, kgf (daN) = 350; 70

b) the diameter of the wear stain at 300 hgf (daN), after one minute, in "mm" = maximum 1.8.

Claims (1)

Claim Composition of greases based on complex thickener, additive for resistance to high pressures, applicable to the lubrication of a wide range of machines operating under severe temperature (-5O ... + 35O ° C) and pressure (minimum 250 kgf) , characterized in that it consists of: 1 ... 7% complex amorphous silica thickener with a minimum silicon dioxide content of 80% and a particle diameter on average of 1 pm, or 1 ... 1,5% 80 talc ; 9 ... 12% organophilic bentonite with gelling degree 4 ... 69; 11 ... 20% mixture of cherry and basic mineral oil or 11 ... 20% polytetrafluoroethylene type polymer; 60 ... 75% fractions of selected naphthenic and / or paraffinic mineral oils, with values of freezing points -5O ...- 2 ° C; 2.5 ... 5% pure synthetic dimethylketone or dimethylketone solution containing 10 ... 20% calcium; 1 ... 8% polyfunctional additives with anti-corrosive, antioxidant and anti-85 wear, having synergistic effect, zinc dialkyl-aryldithiophosphate type or similar effect additives and high pressure additives; 8 ... 28% synthetic colloidal graphite powder mixture with a carbon content of at least 99.5% and molybdenum bisulphide powder of minimum 99.5% and hardness 1 ... 1.5 in Mohs scale with average particle size of 0.6 ... 0.8 pm, or 1 ... 10% additives for high pressures such as synthetic sulphurized esters, iso-90 butene sulphides, organic compounds with sulfur, phosphorus and / or chlorine , or additives with similar effects, the percentages being expressed by weight.