[0001] The present invention relates to a wire rope lubricant being at least partly, optionally substantially, biodegradable, and a wire rope including such a lubricant.

[0002] Wire ropes are well known for both onshore and offshore use, in particular in maritime situations. They can be used in all types of marine vessels, including ships, large boats, drilling units etc, and wire ropes are often selected for their flexibility, strength, resistance to deformation, and bending.

[0003] Wire ropes are generally formed of a number of heavy duty wires first forming strands, and then twisting of a number of the strands together, optionally around or over a core, to form a final wire rope.

[0004] Wire ropes are frequently subject to significant wear and tear, and often some corrosion, especially in maritime situations. It is naturally desired to maintain the highest properties for the wire rope, and to avoid or minimise any damage thereto. Thus, the use of wire rope lubricants to benefit the wire rope in use is well known in the art.

[0005] Some wire rope lubricants are used during the stranding and closure operation of wire rope manufacture, particularly to achieve integration within or around the strands prior to the subsequent twisting. Some wire rope lubricants are alternatively or additionally regularly applied to wire ropes in use to provide or continue any anti-wear or anti-corrosion properties. [0006] Conventional wire rope lubricants comprise a mineral base oil and thickener system, with one or more additives, typically at least an anti- corrosion additive. However, increasing environmental legislation around the world, such as the requirement to obtain a Vessel General Permit to allow a vessel into the waters of the United States of America (based on permissible discharges incidental to the normal operation of a vessel), make the use of conventional wire rope lubricants a challenge.

[0007] Thus, according to one aspect of the present invention, there is a provided wire rope lubricant comprising a majority base fluid component and a minority of a wax or polymer component, wherein at least one of the base fluid and the wax or polymer is biodegradable.

[0008] In this way, the wire rope lubricant can be defined as an 'Environmentally Acceptable Lubricant' (EAL) as currently defined in Appendix A of the USA EPA 2013 Vessel General Permit (VGP) regulation used to define lubricants in the art. In meeting these regulations the product will be classed as biodegradable, minimally toxic and non bio-accumulative.

[0009] The biodegradability of the base fluid, wax or polymer can be measured using the Organisation for Economic Cooperation and Development (OECD) standard methodology known in the art, in particular Test No. 306 entitled "Biodegradability in sea water" (1992).

[0010] The present invention is not limited by the nature of the base fluid, which may comprise one or more different components or fluids, falling within the above definitions. By way of example only, and without limitation, examples of suitable base fluids that are biodegradable include one or more of the following group: vegetable oil, such as rape seed oil, castor oil, soya oil and synthetic esters.

[0011] The base fluid is preferably an oil, and many base oils or possible components therefor are known in the art. A number of these are defined in the Lubricant Substance Classification list (or "LuSC— list), which also sets out their biodegradability and aquatic toxicity. The Lubricant Substance Classification list is a list of substances and brands that have been assessed on its biodegradation/bioaccumulation, aquatic toxicity, and renewability and exclusion lists of substances by a competent body. The assessment is based on a maximum treat rate allowed in a lubricant. The list is published on the EU Ecolabel website.

[0012] Preferably, the base fluid is biodegradable oil having a kinematic viscosity in the range 450— 2000 centistokes (cSt, also being cm ² /s), at 40°C.

[0013] Optionally, the base fluid has a high temperature stability and a low acid value (<0.2 mg KOH/g). The Total Acid Number (TAN) of a base fluid can be measured using the ASTM D974 test procedure.

[0014] Optionally, the base fluid has a viscosity in the range 450-1000 cSt-at a temperature of 40°C, preferably in the range 600-1000 cSt at 40°C, and more preferably in the range 800-900 cSt at 40°C.

[0015] Optionally, the base fluid has a viscosity in the range 40— 450 cSt at a temperature of 100°C, preferably in the range 40— 200 cSt at

100°C, and more preferably in the range 40 - 80 cSt at 100°C.

[0016] Optionally, the wax or polymer of the wax or polymer component of the wire rope lubricant is biodegradable. [0017] In one embodiment of the present invention, both the majority base fluid component and the minority wax or polymer component are both biodegradable.

[0018] Typically, the wax or polymer is a solid or a solid-like substance at ambient

temperature, or any raised ambient temperature such as 40°C.

[0019] Optionally, the wax or polymer has a melting point in the range 70-

100°C.

[0020] Optionally, the viscosity of the base fluid and the viscosity of the melted wax or polymer is the same (within a small range), or wholly or substantially similar, such that the viscosity of the wire rope lubricant including these components is predictable, and the viscosity properties of the components wholly or substantially act in a similar manner during any heating and cooling. This is especially where the wax or polymer is a solid at ambient temperature, and a liquid during any hot application.

[0021] Optionally, the base fluid and wax or polymer lubricant composition maintain a single "phase' (i.e. not becoming 'two-phase') upon heating, especially above the melting point of the wax or polymer.

[0022] Optionally, the wax or polymer comprises 5-15 wt% of the lubricant.

[0023] The wax or polymer may be a naturally occurring or wax or polymer in particular based on plant oil or plant material, or be a synthetic wax or polymer. Preferably, the wax or polymer is able to provide a homogenous mixture with the base fluid, and avoids or has a de minimus of any dissolution or separation on cooling from a higher temperature to an in use or ambient temperature.

[0024] Optionally, the wax is one or more of the group comprising: carnauba wax, rice wax, candililla wax, animal waxes such as beeswax, mineral waxes and synthetic waxes.

[0025] Preferably, the wax is carnauba wax.

[0026] Carnauba wax is a refined wax obtained from the fronds of the Brazilian tropical palm tree Copenicia cerifera and has the CAS no. 8015-86- 9, the ISN No. 903. Carnauba wax has a majority component based on a number of aliphatic esters, and some diesters, as well as containing free acids, free alcohols, hydrocarbons and some resins. It has a melting point in the range 80-86°C. Carnauba wax has an ester value between 71-93.

[0027] A synthetic wax intended to have the same properties of Carnauba wax, or similar or substantially similar properties, is included within the scope of the present application, having in particular wholly or substantially the same viscosity and melting point range.

[0028] Optionally, carnauba wax is useable as the minority component in the range 5- 15 wt%.

[0029] Alternatively, the wax or polymer is polyethylene wax, useable as the minority component from 2-3 wt%.

[0030] Optionally, the wax or polymer is a blend of one or more waxes and/or polymers, which can be blended in order to adjust the consistency and melting range of the final product. [0031] Suitable anti-corrosive, anti-oxidant and anti-wear additives or components are known in the art, and include a range of products sold under the Additin (registered trade mark) brand from RheinChemie including RC4803 and RC8012, as well products sold under the Irganox and Irgalube brand from BASF, including L57 and 349. The products included are from the LuSC list mentioned hereinbefore.

[0032] In the wire rope lubricant of the present invention, the base fluid component may comprise at least 70, 75, 80, 85 wt% of the lubricant, preferably in the range 88-91 wt%.

[0033] In the wire rope lubricant of the present invention, the wax or polymer component may comprise up to 15%, optionally in the range 2-10 wt%.

[0034] In the wire rope lubricant of the present invention the remainder can be quantum satis (q.s.), i.e. sufficient to make up 100 wt%, typically being an anti-corrosive additive up to 5 wt%, an anti-wear additive up to 5 wt% and an anti-oxidant additive up to 2-3 wt%, with an overall percentage generally being up to 13 wt%, typically a maximum of 5-6 wt%.

[0035] Optionally, the wire rope lubricant of the present invention has the formula;

base fluid 88-91 wt% oil

wax or polymer 8-10 wt% carnauba wax

additives q.s.

[0036] Wire rope lubricants can be used both onshore and offshore, and the present invention includes the lubricant being utilised in both applications. Wire rope lubricants are most commonly used on-board vessels or other offshore and maritime situations or locations for maintenance of the wire ropes.

[0037] Wire rope lubricants for in-service use are expected to have a good or high penetration rate into the wire rope, and provide corrosion protection and anti-wear properties. Optionally, wire rope lubricants have or form some adhesive propertiesand some also form a film around the wire rope.

[0038] Some wire rope lubricants are also delineated between 'heavy bodied lubricants' best suited for applications where the wire rope is exposed to an extreme or an abusive environment, and light-bodied lubricants having a lighter consistency toachieve better penetration of the lubricant into the interior of the

wire rope. The wire rope lubricants of the present invention can be adapted for any suitable consistency based on the viscosity of base lubricant and level of wax or polymer thickener.

[0039] Wire rope lubricants can be applied to an existing wire rope using any one of a number of known techniques, including spraying, dipping, painting,

pneumatic or swabbing. Application is possible via automatic lubrication pneumatic 'units' through which a wire rope can pass, (available from Viper, Masto and CoreLube).

[0040] Wire rope lubricants can also be used during manufacture of a wire rope, in particular by application to one or more of the strands of the wire rope by one or more of the above techniques, or by 'hot application', prior to twisting of the strands to form the final wire rope. The applied wire rope lubricant is intended to form a layer or barrier, preferably a film, optionally also as a final outer surface of the wire rope once formed, to help protect the wire rope from corrosion.

[0041] Thus, according to a second aspect of the present invention, there is provided a method of forming a wire rope having a plurality of wire strands, comprising the step of applying a wire rope lubricant as defined herein between the wire strands, typically prior to twisting of the wire strands to form the wire rope.

[0042] Thus, according to another aspect of the present invention, there is provided a wire rope having a plurality of wire strands and including a wire rope lubricant as defined herein.

[0043] Typically, applied wire rope lubricant becomes depleted or contaminated over a period of time, and one or more new or further applications of the wire rope lubricant can be made to a wire rope, typically whilst the wire rope remains in use or in situ.

[0044] According to a further aspect of the present invention, there is provided the use of a wire rope lubricant as defined herein, wherein the lubricant is applied to a wire rope.