The present invention relates to a lubricating grease for open gears, cables, wire ropes, winches, pulleys and other exposed metal surfaces.

Lubricating greases for use with the foregoing and other exposed surfaces need to stick to the surfaces so that they maintain their effectiveness; they should lubricate and provide protection against corrosion; and they should be easy to apply.

Previous lubricants for these uses have been based on:

(1) asphalt, aromatic solvents and organo-lead salts. These are low- cost products, but they are toxic and are now considered hazardous;

(2) conventional grease compositions of oil thickened with metal soap or clay soap. They are considered safe but they are expensive.

An objective of the present invention is to provide a lubricating grease composition which is of low toxicity, environmentally-acceptable, and of low cost.

The present invention provides a lubricating grease composition for open gears, cables, wire ropes and other exposed metal surfaces, comprising a blend of petrolatum and a polyalkene, said blend having and unworked cone penetration according to test ASTM D-217 in the range of from 11.5 to 40.5mm, and preferably in the range of from 12.5 to 38mm.

The polyalkene may comprise one or more polybutenes, and the polybutenes may have a kinematic viscosity at 100°C (KV^QO) ^m the ^ran 8e of from 35,000 to 45,000mm ² /s(cSt), e.g., about 40,000mm ² /s.

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The composition may comprise a resin thickener. The thickener may be selected from aliphatic hydrocarbon resin, polyamide resin, polyimide resin, acrylate resin, isopropylene resin, polyethylene resin, copolymers and mixtures of two or more of the foregoing.

The composition may comprise a hydrocarbon or other liquid softener. A suitable softener is a Bright stock mineral oil fraction, but other softener liquids may be employed as alternatives or in addition thereto.

The composition may comprise at least one fortifying additive selected from, for example, corrosion inhibitors, extreme pressure agents and tackifier agents. The corrosion inhibitor may be an alkenesuccinimide or derivative thereof; the extreme pressure agent may be a molybdenum compound (e.g., molybdenum di(2-ethylhexyl) phosphorodithioate) and the tackifier agent may be a solution in mineral oil of high molecular weight polybutenes.

The present invention also provides a fluid composition of lubricating grease for application in the form of a liquid or aerosol comprising a low viscosity liquid solvent or dispersant, and a lubricating grease composition as described herein dissolved and/or dispersed in the liquid solvent or dispersant. The low viscosity liquid solvent or dispersant may be a relatively volatile environmentally-acceptable liquid hydrocarbon (e.g.: a white spirit).

The fluid composition may be applied to the metal surface to be lubricated and or protected from a mechanical or manual applicator such as a paint brush or in the form of an aerosol. The solvent or dispersant preferably evaporates leaving behind a residue of the lubricating grease composition.

Preferred grease compositions of the invention have compositions (wt %) in the following ranges:

40 to 60 wt % petrolatum

10 to 31 wt % polybutenes

0 to 20 wt % aliphatic resin thickener

0 to 30 wt % brightstock softener

0 to 15 wt % highly refined hydrocarbon solvent (e.g., white spirit)

0 to 5 wt % fortifying additives (anti-corrosion, extreme pressure and/or tackifier agents)

The lubricating greases of the invention can be made in any convenient manner. In one preferred method, the major components (petrolatum, polybutenes, brightstock and/or aliphatic resm) are heated together to a temperature in the range 70 to 120°C to dissolve the polybutene and resm and reduce the viscosity of the resulting mixture for ease of blending. When the components are completely mixed, the temperature of the mixture is reduced (preferably to no more than 70°C) and the desired amounts of the other components are added and mixed in at that temperature until a consistent, homogeneous appearance is obtained.

The final product, when cool, may have a wide range of viscosities (e.g., from 5,000 to 270,000 mm2/s(cSt) at 40 ^β C) according to the relative concentrations of the major components. If the higher viscosity grades are difficult to apply to equipment, they may be heated to reduce their viscosities. Alternatively, they may be thinned by blending with a suitable low viscosity liquid solvent or dispersant so that they can be applied as a liquid or an aerosol. A suitable environmentally-acceptable low viscosity liquid solvent or dispersant is a highly refined paraffinic solvent such as white spirit or kerosene.

The invention is now further described with reference to some non- limitative examples thereof.

In the examples which follow, the components of the lubricating greases were as follows:

1. Petrolatum - Amber Tech 2 (Trade Mark), supplied by Witco BV, having a dropping point (ASTM D-127) in the range 70 to 80°C, a kinematic viscosity (ASTM D-445) at 100°C of 14 to 20mm ² /s (20cSt) and cone penetration (ASTM D-937 of about 90-155 x 0.1mm. The oil content (ASTM D-721) is about 10 to 15 wt %.

2. Polyisobutene - Hyvis 2000 (Trade Mark) supplied by Adibis Ltd and BP Chemicals Ltd., which is composed of polyisobutenes having a number average molecular weight of at least 5,000 and which has a kinematic viscosity at 100°C (KV ₁₀ o) in the range of from 36,000 to 45,000.

3. Resin Thickener - ESCOREZ 1102 (Trade Mark) supplied by Esso Chemical Ltd., which is an aliphatic hydrocarbon resin.

4. Hydrocarbon Liquid Softener - Brightstock, which is a well-known mineral oil liquid fraction boiling of relatively high viscosity boiling in the lubricating oil boiling range.

5. Tackifier - PARATAC, supplied by Esso Chemical Ltd., a 7% solution having mineral oil of polybutenes having a molecular weight of about 10,000.

6. Corrosion Inhibitor - HITEC 536, supplied by Ethyl Petroleum Additives, an alkylene succinimide.

7. Extreme Pressure Agent - MOLYVAN L, supplied by Vanderbilt, a molybdenum di(2-ethylhexyl) phosphorodithioate.

8. Low Viscosity Solvent (Thinner) - VARSOL 40, supplied by Esso Petroleum Co. Ltd., a highly refined paraffinic white spirit.

Three lubricating grease samples, A, B and C were made up by the procedure described herein, and two fluid (e.g. liquid) grease composition, sample D. The composition of the samples is given in Table 1, except that in the case of the fluid samples, sample D contained 6.38 parts by weight (pbw) VARSOL 40 in 106.38 pbw of composition, ie. 6.0 wt % VARSOL 40, and sample Dt contained 7.5 wt % VARSOL 40.

The samples, A, B, C, D and Dt were subjected to standard tests for grease compositions employed on exposed surfaces. The results of the tests are summarised in Tables 2 and 3, from which it will be seen that the samples provided excellent lubrication properties and resistance to extreme pressure loading and corrosion without presenting any significant environmental hazard.

The lubricating composition of the invention provides lubrication and/or protection (e.g., in hostile environments) for open gears (ferrous and bronze), wire ropes, cables (e.g. on hoists), drag line cables, winches, sluice cables, shipboard cables and lines (anchors, mooring and tension tables), inter alia.

TABLE 1

CONCENTRAΗON (WT%)

COMPONENT A B C D

BRIGHTSTOCK 30.00 30.00 • •

AMBERTECH 2 57.00 46.73 47.50 47.50

HYVIS 2000 10.50 20.77 30.00 31.00

ESCOREZ 1102 - • 20.00 19.00

HTTEC 536 0.50 0.50 0.50 0.50

PARATAC 1.00 1.00 1.00 1.00 OLYVAN L 1.00 1.00 1.00 1.00

VARSOL 40 (ESSO WHITE +6.38 SPIRIT 100)

TABLE 2

TEST METHOD A B C D/Dt

VISCOSITY AT 100 ^β c cSt ASTM D445 56.68+ 132.1+ 563.5 258.8

POUR POINT °C ASTM D97 +69 +69 +72 +54

COC FLASH POINT °C ASTM D92 284 270 268 100 / 202t

DROPPING POINT °C IP 396 (MODIFIED) 58.6 64.8 68.6 61.1/69.0t

COPPER STRIP RATING ASTM D130 1B+ IB 1A 1A

CO

DO RUST PREVENTION, SALT ASTM D665B PASS ⁺ (AT 90-C) PASS ^, '+ (AT 90'C) PASS ^* (AT 90-C) PASS (AT 60 ^o C WATER

RUST PREVENTION, ASTM D1748 >180 DAYS++ * • *

CO HUMIDITY CABINET

RUST PREVENTION, SALT ASTM B117 >5 DAYS * >5 DAYS >5 DAYS SPRAY CABINET

3

FZG FAILURE LOAD STAGE A/2.76/50 >12 - >11 >13 r 4-BALL INITIAL SEIZURE IP 239 105 205+ " 105 LOAD (KG)

4-BALL WELD LOAD (KG) IP 239 240 216+ 235 220

4-BALL WEAR SCAR (MM) RT11 0.35 - - 0.35

TIMKEN OK LOAD (LB) IP 326 40 - 50 40

NOTES * STAINING REPORTED + WITHOUT PARATAC ++ WITHOUT HITEC 536

TABLE 3 PANEL ADHESION TEST RESULTS