DK2531587T3

DK2531587T3 - A lubricating grease containing lignin sulfonate, their preparation and use

Info

Publication number: DK2531587T3
Application number: DK11711018.9T
Authority: DK
Inventors: Thomas Litters; Alexander Liebenau
Original assignee: Fuchs Petrolub Se
Priority date: 2010-02-02
Filing date: 2011-01-31
Publication date: 2016-01-25
Also published as: BR112012019181A2; US20120302472A1; CN102770513B; RU2012136909A; WO2011095155A1; KR101833854B1; ES2561821T3; JP5856078B2; AU2011212763B2; PT2531587E; EP2531587B9; CN102770513A; RS54610B1; KR20120139730A; AU2011212763A1; MX2012008960A; CA2788157A1; RU2554873C2; DE102010006745A1; CA2788157C

Description

The invention relates to a process for producing lubricating greases that contain calcium lignin sulfonate, lubricating greases of such kind, and use thereof.

Lignin is a complex polymer based on phenylpropane units, which are cross-linked to each other with a wide variety of different chemical bonds. Lignin is present in plant cells together with cellulose and hemicellulose. Lignin itself is a cross-linked macromolecule with average molecular weights of for example at least 10,000 g/mol (weight average).

There are essentially 3 types of monolignol monomers that can be identified as monomer components of lignin, and they differ in the degree of their methoxyla-tion. They are p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. These lignols are incorporated in the lignin structure in the form of hydroxyphenyl (H)-, guaiacyl (G)- and syringal (S) units. Naked-seeded plants (gymnosperms) such as pine trees contain mostly G units and low proportions of H units. All lignins contain small amounts of incomplete or modified monolignols. The primary function of lignins in plants is to lend them mechanical stability by cross-linking the vegetable polysaccharides. Lignin constitutes about 1/3 of the dry mass of wood, and according to rough estimates 30% of the non-fossil organic carbon mass on Earth. It is the third most abundant organic material after cellulose and chitin, and is thus a very readily available, renewable raw material for industrial products.

Lignin sulfonate is obtained as a by-product of paper manufacturing using the sulfite process. In this process, wood that has been reduced to wood chips is heated for about 7 to 15 hours in the presence of calcium hydrogen sulfite liquor and under pressure (for example 5 to 7 bar) and then the ligninsulfonic acid is removed from the lignocellulose in the form of calcium lignin sulfonate in a washing and precipitation process. Liquors of magnesium, sodium or ammonium sulfide can also be used instead of calcium hydrogen sulfite, and these produce the corresponding magnesium, sodium and ammonium salts of ligninsulfonic acid.

When the washing liquor is evaporated, powdery lignin sulfonates remain. Annual worldwide production of lignin sulfonates is in the order of 55 million tons.

Sodium, calcium and magnesium lignin sulfonates are often used as the raw material for plasticising and liquefying concrete and mortar. Lignin sulfonates are also used as pelletising promoters in the kraft animal feed industry and as dispersing or complexing agents in other fields.

In modern lubricating grease formulations, a not inconsiderable proportion of the formulation cost is devoted to tribochemically acting extreme pressure and anti-wear additives (EP/AW additive), with the result that they often become the price drivers for lubricating greases.

Many of these additives are produced in complicated, multistage synthesis processes, and their use is limited both in terms of the nature of the application and of their effective concentration in the final formulation due to the toxicological side effects that occur in many cases. In some applications, for example in constant velocity joint shafts or in slow running and heavily loaded rolling bearings, deficient lubrication conditions and/or contact between friction partners is unavoidable even when liquid additives are introduced. Former practice in such cases was to use solid lubricants based on inorganic compounds (for example phosphate salts of calcium and zinc), plastic powders (for example PTFE) or metal sulfides (for example M0S2). But these components are also often expensive and can have a critical effect on the overall cost of a lubricant formulation.

Former practice in lubricating grease production was to introduce these additives in a second process step, performed after the actual chemical reaction process of thickener formation. In this method, additives, particularly solid lubricants, must be distributed homogeneously throughout the relatively viscous lubricating grease by intensive mixing and shearing processes with relatively high mechanical effort in order to obtain their optimum effect. From a modern perspective, the following has often proven disadvantageous and prompted the present invention.

Lubricating greases containing sodium lignin sulfonates and sodium soaps or lithium soaps are already known from US 3239537 A. However, these are not suitable for use in lubricating constant velocity joint shafts, mainly because the grease attacks the TPE materials that are used in the bellows.

Usual lubricant additives and solid lubricants are normally based on non-renew-able raw materials and are often poorly biodegradable.

Furthermore, most common anti-wear additives and friction reducing lubricant additives entail expensive chemical synthesis processes, which represent a significant cost factor. Particularly when solid lubricants are used for heavily loaded friction points, materials most frequently used are relatively expensive, for example M0S2 or PTFE.

Object / advantage of the invention

The object of the invention is therefore to avoid the drawbacks of the prior art as described in the preceding, and to make lignin sulfonates available in lubricating greases both as cost-effective structure forming agents and as additives to promote wear resistance, reduce friction and protect against ageing, and at the same time to lend the lubricating greases good water resistance.

The presence of lignin sulfonate means that the use of other common lubricant additives and solid lubricants, particularly M0S2, may be minimised or entirely dispensed with.

Summary of the invention

The invention is defined by the independent claims. Preferred variations represent the objects of the dependent claims or are described in the following.

According to the process on which the present invention is based, first a precursor stage (base grease) is prepared by mixing at least - Base oil - Fatty acids and/or esters or salts thereof, wherein the fatty acid salt is at least partly a calcium salt, for producing soaps and containing at least calcium soaps, - Organic and/or inorganic complexing agents if necessary, - Alkaline earth hydroxides, wherein the alkaline earth hydroxides include at least CaOFI, - Water if necessary (for example as part of the hydroxides), and - Ca-lignin sulfonate having average molecular weights (weight average) greater than 10000 g/mol. and heating to drive out components with low boiling point when esters are used, and to initiate at least one conversion of the alkaline earth hydroxide with the fatty acids and/or esters thereof and the lignin sulfonate, including reacting with the complexing agents if complexing agents capable of reacting with the alkaline earth hydroxides are used, to form a thickener structure in the base oil.

Components with low boiling point are those components that boil at temperatures up to about 100°C under normal pressure, such as water or C1- to C4-al-cohols.

In order to produce the base grease, the mixture is preferably heated to temperatures above 120 °C, or preferably above 180 °C. The conversion to base grease takes place in a heated reactor, which may also be constructed as an autoclave or vacuum reactor.

Then, in a second step the formation of the thickener structure is completed by cooling and any additional components such as additives and/or base oil are added to adjust to the desired consistency or the desired properties profile. The second step may be carried out in the same reactor as was used for the first step, but it is preferable if the base grease is transferred from the reactor to a separate stirred tank reactor for cooling and for mixing in the additional components, if any.

If necessary, the lubricating grease obtained in this way may be homogenised, filtered and/or deaerated.

Preferred substances are Ca/Li-, Li/Ca- and calcium-thickened normal and complex soap greases to which calcium lignin sulfonate has already been added before the reaction phase to produce the base grease and is incorporated into the lubricating grease structure via a thermal process in such manner that it is present in highly homogeneous, oil-insoluble form and results in high dropping point temperatures.

The use of alkaline earth salts, preferably calcium salts, for both the fatty acid salts and for the lignin sulfonate guarantees that salt metathesis does not take place either during the production of the base grease or during the application.

Salt metathesis, particularly with the salts of sodium, must be prevented in order to obtain a lubricating grease containing lignin sulfonate with good water resistance and at the same time a high dropping temperature. For this reason, the use of sodium lignin sulfonate and sodium hydroxide must be avoided. Water resistance is understood to mean that the grease is not emulsified by water and conforms to rating level 1-90 (test at 90 °C) in the test in accordance with DIN 51807-1 (version: 1979-04). Water resistance is further understood to mean that the grease conforms to rating level 1-80 (test at 80 °C) in the test in accordance with DIN 51807-2 (version 1990-03).

The simultaneous application of an excess of alkali in the form of excess calcium hydroxide and possibly also calcium acetate or other calcium salts as the complexing agents is intended to ensure that even small residual amounts of free sulfonic acid groups are neutralised in the lignin sulfonic acid and they lose their hygroscopic, water emulsifying and corrosion promoting action. A high process temperature, above 120 °C and particularly above 180 °C also ensures that the residual moisture that still remains in the lignin sulfonate is evaporated out of the reaction medium completely and any components of the lignin sulfonate that have not been neutralised are neutralised by the calcium hydroxide.

Standard lubricating oils that are liquid at room temperature are suitable for use as base oils. The base oil preferably has a kinematic viscosity from 20 to 2500 mm2/s, particularly from 40 to 500 mm2/s at 40 °C.

The base oils may be classified as mineral oils or synthetic oils. Mineral oils that are eligible for consideration include for example naphthene basic and kerosene basic mineral oils according to their classification in API Group I. Chemically modified low-aromatic and low-sulfur mineral oils with a small fraction of saturated compounds and better viscosity/temperature behaviour than Group I oils, classified as API Group II and III are also suitable.

Regarding synthetic oils, polyethers, esters, polyalphaolefins, polyglycols and alkyl aromatics and mixtures thereof are noteworthy. The polyether compound may contain free hydroxyl groups, but it may also be wholly etherised or terminal group esterified and/or it may be produced from a starter compound having one or more hydroxy and/or carboxyl groups (-COOH). Polyphenyl ethers, whether alkylated or not, are also possible as the sole component, or better still as components of a mixture. Esters of an aromatic di-, tri- or tetracarboxylic acid with one or more C2- to C22 alcohols present in mixture, alcohols, esters of adipic acid, sebacic acid, trimethylolpropane, neopentyl glycol, pentaerythritol or dipentaerythritol with aliphatic, branched or linear, saturated or unsaturated C2 to C22 carboxylic acids, C18 dimer acid esters with C2 to C22 alcohols, complex esters, as single components or in any mixture thereof, are also suitable for use.

The soaps produced are either pure calcium soaps or mixtures containing calcium soaps, besides calcium soaps particularly lithium soaps and/or aluminium soaps of one or more saturated or unsaturated monocarboxylic acids having 10 to 32 carbon atoms, substituted or not, particularly having 12 to 22 carbon atoms, particularly preferably corresponding hydroxycarboxylic acids. Suitable carboxylic acids are for example lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid or behenic acid and preferably 12-hydroxystearic acid. Even corresponding low alcohol esters, such as corresponding triglycerides and the methyl-, ethyl-, propyl-, isopropyl- or sec.-butyl esters of acid/hydroxy acid, may be used with saponification instead of the free acid group to achieve better dispersion.

The soap is converted into a complex soap by the presence of a complexinq agent. The lubricating grease compositions according to the invention containing the complex soaps (presence of a complexinq agent) have higher dropping points, for example higher than 200 °C (DIN ISO 2176). Appropriate quantities for the addition of the complexing agent are from 0.5 to 20 wt %, particularly 0.5 to 10 wt %.

The following complexing agents are advantageous for the purposes of the present invention: (a) alkali salt (preferably lithium salt) except sodium salt, alkaline earth salt (preferably calcium salt) or aluminium salt of a saturated or unsaturated monocarboxylic acid, or also hydroxycarboxylic acids having 2 to 8, particularly 2 to 4 carbon atoms, or a dicarboxylic acid having 2 to 16, particularly 2 to 12 carbon atoms, each of which may be substituted or unsubstituted, and/or (b) the alkaline and/or alkaline earth salt of boric acid and or phosphoric acid, particularly the products of its reaction with LiOH and/or Ca(OH)2.

Complexing agent (a) is preferably solely a calcium salt, particularly if this is used as calcium acetate to produce the base grease. Acetic acid and propionic acid are particularly suitable for use as monocarboxyl ic acids. Hydroxybenzoic acids such as parahydroxybenzoic acid, salicylic acids, 2-hydroxy-4-hexylbenzoic acid, metahydroxybenzoic acid, 2,5-dihydroxybenzoic acid (gentisic acid), 2,6-dihy-droxybenzoic acid (gamma-resorcylic acid) or 4-hydroxy-4-methoxybenzoic acid are also suitable. Particularly suitable dicarboxylic acids are adipic acid (C6H10O4), sebacic acid (C10H18O4), azelaic acid (C9H16O4) and/or 3-te/t-butyl-adipic acid (C-ioH-isCU).

Possible substances for use as the borate (b) would include for example metaborate, diborate, tetraborate or orthoborate, such as monolithium orthoborate or calcium orthoborate. The phosphates might be selected from alkaline (preferably lithium) and alkaline earth (preferably calcium) dihydrogen phosphate, -hydrogen phosphate, or -pyrophosphate.

Optionally, bentonites, such as montmorillonite (in which some or all of the sodium ions may have been substituted with ammonium ions), aluminosilicates, clays, silicic acid (e.g. aerosil), oil-soluble polymers (e.g., polyolefins, poly(meth)acrylates, polyisobutylenes, polybutenes or PS) or also di- and polyureas may also be used as co-thickeners. The bentonites, aluminosilicates, clays, silicic acid and/or oil-soluble polymers may be added to produce the base grease or introduced as additives later, in the second step. The di- and polyureas may be introduced as additives.

The compounds according to the invention may also contain other additives as additional substances. Common additional substances for the purposes of the invention are antioxidants, anti-wear agents, corrosion protection agents, detergents, dyes, lubrication enhancers, viscosity additives, friction reducers and high-pressure additives.

Examples of such would be: - Antioxidants such as amine compounds (e.g. alkylamines or 1 -phenyl-ami-nonaphthaline), aromatic amines, e.g. phenyl-naphthyl amines or diphenyl amines, phenol compounds (e.g., 2.6-di-tert-butyl-4-methylphenol), sulfur antioxidants, zinc dithiocarbamate or zinc dithiophosphate; - High-pressure additives such as organic chlorine compounds, sulfur, phosphorus or calcium borate, zinc dithiophosphate, organic bismuth compounds; - Substances designed to improve “oiliness”, such as C2- to C6- polyols, fatty acids, fatty acid esters or animal or vegetable oils; - Anticorrosion agents such as petroleum sulfonate, dinonylnaphthalene sulfonate or sorbitan esters; - Metal deactivators such as benzotriazol or sodium nitrite; - Viscosity enhancers, such as polymethacrylate, polyisobutylene, oligo-dec-1-ene, and polystyrenes; - Anti-wear additives and friction reducers such as organomolybdenum complexes (OMC), molybdenum-di-alkyl-dithiophosphates, molybdenum-di-alkyl-dithiocarbamates or molybdenum sulfide-di-alkyl dithiocarba-mates, particularly molybdenum-di-n-butyl dithiocarbamate and molybdenum disulfide-di-alkyl dithiocarbamate (Mo20mSn(dialkyl carbamate)2 where m = 0 to 3 and n = 4 to 1), - Friction reducers such as functional polymers, e.g. oleyl amides, organic polyether- and amide-based compounds, for example alkyl polyethylene glycol tetradecylene glycol ether.

In addition, the lubricating grease compounds according to the invention also contain usual additives for protection against corrosion, oxidation and attack by metals, which function as chelating compounds, radical scavengers, UV converters, reaction layer forming agents and the like.

Solid lubricants may be selected for example from the group of polymer powders such as polyamides, polyimides or PTFE, graphite, metal oxides, boron nitride, metal sulfides such as molybdenum sulfide, tungsten disulfide or sulfide mixtures with tungsten, molybdenum, bismuth, tin and zinc base, inorganic salts of alkali and alkaline earth metals, such as calcium carbonate, sodium and calcium phosphates. Solid lubricants may be divided into the following four groups: compounds with a lattice layer structure, such as molybdenum disulfide and tungsten disulfide, graphite, hexagonal boron nitride and certain metal halides; oxidic and hydroxidic compounds of the transition and alkaline earth metals and carbonates or phosphates thereof; soft metals and/or plastics. The desired, advantageous lubricating properties may be adjusted with the use of lignin sulfonates with having to use solid lubricants. In many cases, solid lubricants may be omitted entirely, or at least significantly reduced. If solid lubricants are used, graphite is the most favourable.

Lignin sulfonate may be chosen from calcium lignin sulfonates have a molecular weight (Mw, weight average) greater than 10,000, particularly greater than 12,000 or even greater than 15,000 g/mol, for example from 10,000 up to 65,000 g/mol or 15,000 - 65,000 g/mol and particularly containing 2 to 12 wt %, particularly 4 to 10 wt %, sulfur (calculated as elemental sulfur) and/or 5 to 15 wt %, particularly 8 to 15 wt % calcium (calculated Ca). Besides, calcium lignin sulfonates, other alkaline earth lignin sulfonates may also be used. The average molecular weight (weight average) is determined for example by size exclusion chromatography. A suitable method is the SEC-MALLS method as described in the article by G. E. Fredheim, S. M. Braaten and B.E. Christensen, “Comparison of molecular weight and molecular weight distribution of softwood and hardwood lignosulfonates" published in “Journal of Wood Chemistry and Technology”, Vol. 23, No. 2, pages 197-215, 2003 and the article “Molecular weight determination of lignosulfonates by size exclusion chromatography and multi-angle laser scattering” by the same authors, published in the “Journal of Chromatography A”, Volume 942, edition 1-2, 4 January 2002, pages 191-199 (mobile phase: Phosphate DMSO-SDS, stationary phase: Jordi-Glu-kose-DVB as described in 2.5). Suitable calcium lignin sulfonates are for example the commercially available products Norlig 11 D and Borrement Ca 120 produced by Borregard Lignotech.

The lubricating grease according to the invention is characterized by features of claim 14 and the lubricating grease, as applied in the process of the invention, by the preferred features of claim 6.

It was found that lignin sulfonates function as structure forming agents for water-resistant lubricating greases that also have properties as a solid lubricants or anti-wear additives and ageing stabilisers. At the same time, lignin sulfonate was observed to have surprisingly synergistic effects with other solid lubricants, for example with graphite or calcium carbonate.

It was also found that lignin sulfonates serve as multifunctional components for lubricants. Due to the large number of polar groups and aromatic structures they contain, their polymer structure and their low solubility in all types of lubricating oils, lignin sulfonates are suitable for use not only as a thickener component but also as solid lubricants in lubricating greases and lubricating pastes. Their sulfur content also enhances their EP/AW effect in the lubricating greases and the phenolic structures provide an age-inhibiting effect.

It is assumed that due to the large number of polymer and polar aromatic units it contains, the lignin sulfonate structure is predominantly planar.

Accordingly, they are able to be deposited very well in layer structures on metal surfaces under due to the effect of external frictional and shearing forces, because the aromatic nuclei of the lignin sulfonate enter into an associative reciprocal action with the metal surface, and metallic friction partners are separated from each other effectively and permanently even under heavy loads and high pressures.

If calcium lignin sulfonate is added before the start of the reaction phase during the production of soap thickeners, particularly of calcium complex soaps, not only is the thickening effect of these soaps enhanced with a high dropping point, but the anti-wear protection and lubrication effects of corresponding lubricating grease formulations are also enhanced. Consequently, it is beneficial for the distribution and effect of additives and solid lubricants if they are chemically or mechanically incorporated in the thickener structure as an additional structural element in situ during the reaction phase.

According to the prior art, it is necessary in many cases to use specially treated, expensive fatty acids, such as 12-hydroxystearic acid, or special complexing agents such as borates or salts of acetic acid, sebacic acid and azelaic acid to manufacture soap greases with high dropping points, yet these substances have little or no additional effect as anti-wear protection and friction reducing additives. If Ca-lignin sulfonates are included, the use of these other components may be reduced significantly or even dispensed with altogether. The use of Ca-lignin sulfonates further offers the capability to formulate high-performance lubricating greases on the basis of renewable raw materials and abandon an additive-orientated chemistry that is detrimental to the environment.

If oils consisting of unmodified or easily modified native fatty acid esters are thickened using metal soaps based on animal or vegetable fatty acids, and if lignin sulfonates are used as the only additional thickening agent and at the same time the only additive component, lubricating greases are obtained that have been produced almost exclusively on the basis of renewable raw materials, the only exception being calcium hydroxide used for the metal soaps. These greases protect against ageing and wear, and have the effect of raising the seizure load and lowering friction when lignin sulfonates are included as a thickener component.

The lubricating greases according to the invention are particularly suitable for use in or for constant velocity joint shafts, rolling bearings and gearboxes.

If the base oils used consist of readily biodegradable esters, such as those that contain mostly renewable raw materials, the lubricating greases are also suitable for total loss lubrication in the environmentally sensitive area (for example in mining or agriculture).

In the special case of lubrication for maintenance-free constant velocity joint shafts, the first lubricating grease has been formulated using calcium lignin sulfonate that differs from the prior art in that it assures long operating life and good levels of efficiency entirely without the use of M0S2 and other organic and inorganic molybdenum compounds.

The absence of other additives also serves to lower the friction coefficient, protect against seizure load and wear and renders the product highly compatible with the materials used in standard commercial constant velocity joint shaft bellows, such as chloroprene rubber and thermoplastic polyether esters. Since the sulfur contained in lignin sulfonate is bound by thermally stable sulfonate groups, unlike the bound sulfur in conventional additives it is only released at very high temperatures and/or with very high levels of activation energies, such as do not occur in lubricating grease applications except with tribocontacts under very high loads. In this way, subsequent vulcanisation or crosslinking of rubber materials by the sulfur released from ageing lubricant is largely prevented.

If calcium lignin sulfonate is used in a lubricating grease formulation that has been adjusted with excess calcium hydroxide to be overbasic, this prevents free lignin sulfonic acid from having a hydrolytic effect on materials used in the bellows, such as thermoplastic polyether esters. A special aspect of the present invention is that it may be used to obtain cost-optimised lubricating grease formulations for lubricating points that are under heavy load, such as in constant velocity joints in particular, and that are well compatible with bellows containing, for example, thermoplastic polyether esters (TPE) and chloroprenes (CR), while offering a high degree of efficiency, low wear and a long service life.

Examples of production Example A (comparison example): 958 g tallow fatty acid, 958 g beef tallow, 958 g calcium acetate, 27.7 g trisodium phosphate, 27.7 g calcium borate and 358 g calcium hydroxide were placed in a reactor in 12,000 g of a base oil mixture and 150 ml water was added. This base was heated to 198 °C in a defined temperature programme while stirring so that the added water and the reaction water evaporated. Additives (see table) were added to the base at certain temperatures during the cooling phase. After the base was adjusted to the desired consistency by adding 3700 g of the base oil mixture, the final product was homogenised in a toothed colloid mill. The grease obtained thereby is suitable for use as constant velocity joint shaft grease, for example.

Example B: 460 g tallow fatty acid, 445 g beef tallow, 460 g calcium acetate, 27.7 g trisodium phosphate, 27.7 g calcium borate and 168 g calcium hydroxide and 920 g calcium lignin sulfonate (Norlig 11D powder manufactured by Borregard Ligno-tech) were placed in a reactor in 14,000 g of a base oil mixture and 150 ml water was added. This base was heated to 208 °C in a defined temperature programme while stirring so that the added water and the reaction water evaporated. Additives (see table) were added to the base at certain temperatures during the cooling phase. After the base was adjusted to the desired consistency by adding 3450 g of the base oil mixture, the final product was homogenised in a toothed colloid mill. The grease obtained thereby is suitable for use as constant velocity joint shaft grease, for example.

Example C (comparison example): 800 g 12-hydroxy stearic acid, 288 g sebacic acid, 388 g calcium acetate and 157.3g calcium hydroxide were placed in a reactor in 5000 g of a base oil mixture. 64 g LiOH x H2O was dissolved in 250 ml water and added. This base was heated to 200 °C in a defined temperature programme while stirring so that the added water and the reaction water evaporated. Additives were added to the base at certain temperatures during the cooling phase.

After the base was adjusted to the desired consistency by adding 3116 g of the base oil mixture, the final product was homogenised in a toothed colloid mill. The grease obtained thereby is suitable for use as rolling bearing grease, for example.

Example D: 600 g 12-hydroxy stearic acid, 216 g sebacic acid, 291 g calcium acetate and 720 g calcium hydroxide and 300 g calcium lignin sulfonate (Norlig 11D powder manufactured by Borregard Lignotech) were placed in a reactor in 5000 g of a base oil mixture. 48 g LiOH x H2O was dissolved in 250 ml water and added. This base was heated to 200 °C in a defined temperature programme while stirring so that the added water and the reaction water evaporated. Additives were added to the base at certain temperatures during the cooling phase.

Example E (comparison example): 1380 g tallow fatty acid, 1360 g beef tallow, 80 g trisodium phosphate, 80 g calcium borate, 1400 g calcium acetate and 493 g calcium hydroxide were placed in a reactor in 12,000 g of a base oil mixture and 150 ml water was added. This base was heated to 230 °C in a defined temperature programme while stirring so that the added water and the reaction water evaporated. Additives (see table) were added to the base at certain temperatures during the cooling phase. After the base was adjusted to the desired consistency by adding 3125 g of the base oil mixture, the final product was homogenised in a toothed colloid mill. The grease obtained thereby is suitable for use as rolling bearing grease, for example.

Example F: 1260 g tallow fatty acid, 1240 g beef tallow, 80 g trisodium phosphate, 80 g calcium borate, 1278 g calcium acetate, 493 g calcium hydroxide and 885 g calcium lignin sulfonate (Norlig 11D Powder manufactured by Borregard Lignotech) were placed in a reactor in 12,000 g of a base oil mixture and 150 ml water was added.

This base was heated to 225 °C in a defined temperature programme while stirring so that the added water and the reaction water evaporated. Additives were added to the base at certain temperatures during the cooling phase. After the base was adjusted to the desired consistency by adding 3125 g of the base oil mixture, the final product was homogenised in a toothed colloid mill. The grease obtained thereby is suitable for use as rolling bearing grease, for example.

Example G (comparison example): 975 g calcium-12 hydroxy stearate, 225 g calcium acetate and 15 g calcium borate were placed in a reactor in 3500 g methyl oleate ester. This base was heated to 200 °C in a defined temperature programme while stirring. Additives were added to the base at certain temperatures during the cooling phase. After the base was adjusted to the desired consistency by adding 180 g methyl oleate ester, the final product was homogenised in a 3-roller mill. The lubricating grease obtained thereby is made on the basis of predominantly renewable raw materials.

Example H: 841 g calcium 12-hydroxy stearate, 219.5 g calcium acetate, 15 g calcium borate and 418 g calcium lignin sulfonate (Norlig 11D Powder manufactured by Borregard Lignotech) were placed in a reactor in 1965 g methyl oleate ester. This base was heated to 200 °C in a defined temperature programme while stirring. Additives were added to the base at certain temperatures during the cooling phase. After the base was adjusted to the desired consistency by adding 1684 g trimethylolpropane trioleate ester, the final product was homogenised in a 3-roller mill. The lubricating grease obtained thereby is made on the basis of predominantly renewable raw materials.

Examples I and J:

The products of example formulations I and J are similar to the production of example H but with the use of different quantities of calcium-12 hydroxy stearate, calcium acetate and calcium lignin sulfonate and different compositions of ester base oils. The lubricating greases obtained thereby are made on the basis of predominantly renewable raw materials.

Table 1: Joint shaft grease formulations

Example A B

Reference Invention calcium com-

Description plex calcium complex with 6% lignin sul-with MoS2 fonate 1. Thickener: 1.1 Lignin sulfonate:

Calcium lignin sulfonate 0.0 6.1 1.2 Fatty acids/-triglycerides:

Mixed fatty acids 4.8 2.9

Mixed triglycerides 4.8 2.8 1.3 Alkali hydroxide:

Ca(OH)2 1.8 1.5 1.4 Complexing agent:

Ca acetate 4.8 3.0

Ca borate 0.1 0.2 2. Base oils:

Mixed basic mineral oil (at v40= 100mm2/s) 79.5 80.8 3. Additives:

Antioxidant 1 0.6 0.5

Antioxidant 2 0.6 0.5

Corrosion protection 0.5 0.2

Solid lubricant, graphite 0.5 1.0

Solid lubricant, MoS2 1.8 0.0

Total 100 100 4. Characteristics Method Unit 4.1 General physical data

Penetration unworked DIN ISO 2137 0.1 mm 263 315

Penetration worked 60 double cycles DIN ISO 2137 0.1 mm 351 340

Copper corrosion 24h /100 °C DIN 51811 Evaluation level 1-100 1-100

Dropping point DIN ISO 2176 °C 240 280

Oil separation 18 h/40 °C DIN 51817 % 0.4 2.1

Oil separation 7 d/40 °C DIN 51817 % 2 8.9 4.2 Water resistance

Static water resistance 3 h/90 °C DIN 51807-1 Evaluation level 1-90 1-90

Washout loss at 80 °C DIN 51807-2 Evaluation level 1 1

Table 1 (continued): Joint shaft grease formulations

Example A B

Reference Invention calcium

Description complex calcium complex with 6% lignin sul-with MoS2 fonate 4.3 Friction reduction

SRV at 80 °C (40 Hz, 1.5 mm Amplitude, 500N load) ASTM D D5707-05

Friction coefficient 0.107 0.097

Process steady steady SRV at 150 °C (40Hz, 1.5 mm Amplitude, 500N load) ASTM D D5707-05

Friction coefficient 0.097 0.085

Process steady steady 4.4 Anti-wear protection

VKA weld load DIN 51350-4 N 3400 3800 N VKA calotte 1000N/1 min DIN 51350-5 mm 1.02 0.62 4.5 Compatibility with bellows materials

4.6.1 Chloroprene Inepsa 4012 168 h/120 °C -Shore A DIN 53505 -2 -1 -Volume change DIN 53521 % +3.5 -0.5 -Change in tensile strength DIN 53504 % -0.5 -1.2 -Change in elongation DIN 53504 % -22.1 -19 4.6.2 NBR rubber SRE NBR 34 7d/100 °C DIN 53538-3 -Shore A DIN 53505 -2 -3 -Volume change DIN 53521 % +3.4 +3.1 -Change in tensile strength DIN 53504 % -2.9 - 5 -Change in elongation DIN 53504 % -7.8 -4.5 4.6.3 TPE elastomer

H ytre I 8332 336h/125 °C -Shore D DIN 53505 -3 -2 -Volume change DIN 53521 % +13.1 +6.2 -Change in tensile strength DIN 53504 % -32.9 + 6.7 -Change in elongation DIN 53504 % -27 +61

Arnitel EB 463 336h/125 °C -Shore D DIN 53505 -6 0 -Volume change DIN 53521 % +10.7 +10.2 -Change in tensile strength DIN 53504 % -is -19.7 -Change in elongation DIN 53504 % -10 +7.8

4.6.4 EPDM rubber Vamac Y76HR 336h/125 °C -Shore A DIN 53505 +3 + 5 -Volume change DIN 53521 % +6 + 0.3 -Change in tensile strength DIN 53504 % -17.4 -1.8 -Change in elongation DIN 53504 % -39 - 35 5. Service life test on the constant velocity joint shaft

Service life Overrollings (mill.) 13.6 11.2

Average steady-state temperature °C 41.1 38.8

Table 2: Rolling bearing grease formulations

Example C D E F

Reference Invention Reference Invention

Calcium/Lithium Calcium/Lithium Calcium/Lithium

Description complex complex Calcium Complex complex with 6% lignin sul- with 5% lignin sulfonate fonate 1. Thickener: 1.1 Lignin sulfonate:

Calcium lignin sulfonate 0.0 6.0 0 5.1 1.2 Fatty acidsMriglycerides: 12-HSA 8.0 5.0

Mixed fatty acids 6.9 5.6

Mixed triglycerides 6.8 5.4 1.3 Alkali hydroxide:

LiOH*H20 0.6 0.4

Ca(OH)2 1.6 1.0 2.5 2.0 1.4 Complexing agent:

Sebacic acid 2.9 1.8

Ca acetate 3.9 2.4 7.0 5.7

Ca borate 0.4 0.3 2. Base oils:

Mixed basic mineral oil (at v40= 100 mm2/s) 81.6 82.0 75.6 75.3 3. Additives:

Antioxidant 1 0.2 0.2 0.2 0.2

Antioxidant 2 0.2 0.2 0.2 0.2

Corrosion protection 1 1 0.4 0.3

Total

Table 2 (continued): Rolling bearing grease formulations

Example C D E F

Reference Invention Reference Invention

Calcium/Lithium Calcium/Lithium Calcium/Lithium

Description complex complex Calcium Complex complex with 6% lignin sul- with 5% lignin sulfonate fonate 4. Characteristics Method Unit 4.1 General physical data

Penetration unworked DIN ISO 2137 0.1 mm 299 278 199 196

Penetration worked, 60 double cycles DIN ISO 2137 0.1 mm 310 299 234 242

Dropping point DIN ISO 2176 °C 206 230 255 >260

Oil separation 18 h/40 °C DIN 51817 % 2.2 1.1 0 0

Oil separation 7 d/40 °C DIN 51817 % 4.1 3.9 0.8 0.6 4.2 Water resistance

Static water resistance 3 h/90 °C DIN 51807-1 Evaluation level 1-90 1-90 1-90 1-90

Washout loss at 80 °C DIN 51807-2 Evaluation level 1111 4.3 Corrosion protection

Emcor distilled water DIN 51802 Evaluation level 0-0 0-0 0-0 0-0 4.5 Anti-wear protection efficiency VKA weld load DIN 51350-4 N 2000 3400 2000 3200 VKA calotte 1000N/1 min DIN 51350-5 0.1 mm 0.91 0.45 0.89 0.67 5. Rolling bearing tests FAG-FE9 (A/1500/6000/120 °C) DIN51821-2

Average operating life L10 78 110 35 78

Average operating life L50 115 220 74 156

Table 3: Lubricating grease formulation with base oils from renewable raw materials

Example G Η I J

Reference Invention Invention Invention

Calcium Com- Calcium

Description plex Calcium Complex Calcium Complex Complex 1. Thickener: 1.1 Lignin sulfonate: -Calcium lignin sulfonate 0 7.1 9.9 5.1 1.2 Finished soaps:

Ca-12 hydroxy stearate 19.5 14.1 19.8 10.1 1.6 Complexing agent:

Ca acetate 4.5 2.9 4.0 2.1

Ca borate 0.3 0.2 0.3 0.1 2. Base oils:

Trimethylol propane trioleate 28.5

Methyl oleate 73.6 73.6 63.9 52.1 3. Additives:

Antioxidant 0.1 0.1 0.1 0.1

Corrosion protection 2 2.0 2.0 2.0

Total 100 100 100 100 4. Characteristics Method Unit 4.1 General physical data

Penetration unworked DIN ISO 2137 0.1 mm 189 108 170 232

Penetration worked, 60 double cycles DIN ISO 2137 0.1 mm 221 209 219 301

Copper corrosion 24h /100 °C DIN 51811 Evaluation level 1-100 1-100 1-100 1-100

Dropping point DIN ISO 2176 °C 210 250 248 205

Oil separation 18h/40 °C DIN 51817 % 0.4 0.0 0.0 0.4 q

Oil separation 7d/40 °C DIN 51817 % 0.6 0.5 0.1 2.5ρς 4.2 Water resistance m

Static water resistance 3h/90 °C DIN 51807-1 Evaluation level 1-90 1-90 1-90 1 -90^0

4.3 Corrosion protection fO

Emcor distilled water DIN 51802 Evaluation level 1-1 1-1 1-1 1-1 £2 4.5 Anti-wear protection VKA weld load DIN 51350-4 N 2000 2800 3000 240C§o VKA calotte 1000N/1 min DIN 51350-5 0.1 mm 0.89 0.67 0.54 0.48^

Claims

A process for preparing lignin sulfonate-containing grease, comprising: (a) the step of bringing together: at least one base oil, at least one calcium soap of a saturated or unsaturated monocarboxylic acid of 10 to 32 carbon atoms, substituted, if appropriate, at least one complexing agent; selected from: (i) an alkali salt, with the exception of sodium salt, an alkaline earth salt or aluminum salt, a saturated or unsaturated monocarboxylic acid or hydroxy carboxylic acid having 2 to 8, a dicarboxylic acid having 2 to 16 carbon atoms, each being (ii) an alkali and / or alkaline earth salt of boric and / or phosphoric acid, including their reaction products with LiOH and / or Ca (OH) 2, and (iii) mixtures thereof, and at least average molecular weight calcium lignin sulfonate by weight average of more than 10,000 g / mol, heating to more than 120 ° C for reaction and during expulsion of low-boiling components, to produce a base and b) the step of cooling and adding base oil and, where appropriate, additives during mixing.

Process according to claim 1, characterized in that in step a), calcium hydroxide is added in addition to, where appropriate, additional alkaline earth hydroxides.

Process according to claim 1, characterized in that the grease is adjusted alkaline, especially by adding calcium hydroxide in excess.

Process according to claim 1, characterized in that heating is carried out to temperatures of more than 180 ° C.

Process according to claim 1, characterized in that in addition to calcium hydroxide in step a) lithium hydroxide, magnesium hydroxide and / or aluminum hydroxide are used, respectively. aluminum alcoholate and / or alumina alcohol and / or lithium, magnesium and / or aluminum soaps of a saturated or unsaturated monocarboxylic acid having 10 to 32 carbon atoms, if substituted.

Process according to claim 1, characterized in that the lubricating grease independently contains: 55 to 92% by weight, especially 70 to 85% by weight of the base oil, 0 to 40% by weight, especially 2 to 10% by weight of additives, 3 to 40% by weight. %, especially 5 to 20% by weight of the calcium soaps and 0.5 to 10% by weight of the complexing agents, and 1 given excess Ca (OH) 2 excess, preferably 0.01 to 2% by weight, and 0.5 to 15% by weight , and more preferably 4 to 8% by weight of calcium lignin sulfonate, if appropriate, in addition to additional alkaline earth lignin sulfonates, each relative to the overall composition of the grease.

Process according to claim 1, characterized in that the base fat from step a) can be prepared using 40 to 70 wt.%, Especially 45 to 60 wt.% Of the base oil, 10 to 60 wt.%, Especially 15 to 50 wt.% Of the calcium soaps. and 5 to 30% by weight of complexing agent, and, where appropriate, excess Ca (OH) 2, preferably 0.02 to 4% by weight, and 0.7 to 30% by weight of calcium lignin sulfonate, if appropriate, in addition to additional alkaline earth lignin sulfonates, each especially in relation to the composition of the base fat.

Process according to claim 1 or 4, characterized in that the lubricating grease contains 0.2-5% by weight graphite and / or no solid lubricant or less than <1% by weight solid lubricant, especially no MO 2.

Process according to claim 1, characterized in that the calcium soaps are prepared in situ as a reaction product of calcium hydroxide, with a saturated or unsaturated monocarboxylic acid having 10 to 32 carbon atoms, especially with 16 to 20 carbon atoms, when substituted, for example by hydroxy, such as ester or anhydride.

Process according to claim 1, characterized in that the complexing agent as a reaction product of a calcium salt, especially calcium hydroxide, with a saturated or unsaturated monocarboxylic acid having 2 to 8, especially 2 to 4 carbon atoms or a dicarboxylic acid having 2 to 16, especially 2 to 12 carbon atoms , each of which is optionally substituted, for example by hydroxy, such as ester or anhydride, is added under step a).

Process according to claim 1, characterized in that the complexing agent is a calcium salt of a carboxylic acid and is prepared in situ during step a), by supplying a saturated or unsaturated monocarboxylic acid with 2 to 8, in particular 2 to 4 carbon atoms or a dicarboxylic acid having 2 to 16, especially 2 to 12 carbon atoms, each optionally substituted, for example, by hydroxy, such as ester or anhydride.

Process according to at least one of claims 1 to 11, characterized in that the calcium lignin sulfonate is dehydrated prior to administration to values of less than 0.5% by weight of water, for example by heating in the base oil to above 95 ° C, especially above 100 To, for example, 120 ° C.

Process according to at least one of claims 1 to 12, characterized in that the composition contains 0.5 to 10% by weight of complexing agent.

A grease composition comprising - 55 to 92 wt%, especially 70 to 85 wt%, of the base oil, - 0 to 40 wt%, especially 2 to 10 wt%, additives, - 3 to 40 wt%, especially 5 to 20 wt. by weight, calcium soaps of a saturated or unsaturated monocarboxylic acid having 10 to 32 carbon atoms, substituted where appropriate, - 0.5 to 10% by weight of complexing agent selected from: (i) an alkali salt, with the exception of sodium salt, an alkaline earth salt or aluminum salt, a saturated or unsaturated mono-carboxylic acid or hydroxy-carboxylic acid of 2 to 8, a dicarboxylic acid of 2 to 16 carbon atoms, each optionally substituted, (ii) an alkali and / or alkaline earth salt of boric acid and / or phosphoric acid, including their reaction products with LiOH and / or Ca (OH) 2, where appropriate, excess Ca (OH) 2, preferably 0.01 to 2% by weight, and (iii) mixtures thereof, and - 0.5 to 15% by weight, and especially preferably 2 to 8% by weight, calcium lignin sulfonate, if appropriate, in addition to additional alkaline earth lignin sulfonates, each relative to the overall composition of the grease, the composition having a cone penetration value (Walk penetration) of 265 to 385 mm / 10 at 25 ° C determined in accordance with ISO 2137.

Composition according to claim 14, characterized in that the composition has a cone penetration value (Walk penetration) of 285 to 355 mm / 10, determined in accordance with ISO 2137.

Composition according to at least one of claims 14 or 15, characterized in that the base oil has a kinematic viscosity of 20 to 2500 mm 2 / s, preferably of 40 to 500 mm 2 / s, at 40 ° C.

Composition according to at least one of claims 14 to 16, characterized in that the complexing agent consists of: an alkali salt, preferably lithium salt, alkaline earth salt preferably calcium salt, or aluminum salt, of a saturated or unsaturated monocarboxylic acid having 2 to 8, especially 2 to 4. carbon atoms or a dicarboxylic acid having 2 to 16, especially 2 to 12 carbon atoms, each substituted as appropriate.

Composition according to at least one of claims 14 to 17, characterized in that the additive comprises one or more members selected from the following group: amine compounds, phenol compounds, sulfur-containing antioxidants, zinc dithiocarbamate or zinc dithiophosphate as antioxidant; organic chlorine compounds, sulfur, phosphorus or calcium borate, zinc dithiophosphate, organic bismuth compounds as high pressure additives; C2 to C6 polyol, fatty acids, fatty acid ester or animal or vegetable oil; petroleum sulfonate, dinonyl naphthalone sulfonate or sorbitan ester as anti-corrosion agent; benzotriazole or sodium nitrite as metal deactivators; polymethacrylate, polyisobutylene, oligo-dec-1-ene, and polystyrene as viscosity enhancer; molybdenum di-alkyl dithiocarbamate or molybdenum sulfide di-alkyl dithiocarbamate or aromatic amine as abrasion protection additive; functional polymers such as, for example, oleylamide, organic compounds on a polyether and amide basis, or molybdenum dithiocarbamate as a friction modifier; and polymer powders such as polyamide, polyimide or PTFE, graphite, metal oxide, boron nitride, metal sulfide such as, for example, molybdenum disulfide, tungsten disulfide or mixture sulphide based on tungsten, molybdenum, bismuth, tin and zinc, inorganic salts of alkali and alkaline earth metal, for example calcium and calcium phosphate, as solid lubricants.

Composition according to at least one of claims 14 to 18, characterized in that the lubricating grease is water-resistant and that is, a) in accordance with the test in accordance with DIN 51807-1 of assessment steps 1-90 and / or b) in accordance with with the test in accordance with DIN 51807-2 of assessment stage 1-80.

Composition according to at least one of claims 14 to 19, characterized in that the calcium lignin sulfonate has an average molecular weight (Mw, weight average) of more than 10,000, in particular more than 12,000 or even more than 15,000 g / mol, which independently contains 2 to 12 wt%, especially 4 to 10 wt%, sulfur (calculated as elemental sulfur) and / or further independently contains 5 to 15 wt%, especially 8 to 15 wt% calcium.

Composition according to at least one of claims 14 to 20, characterized in that the lubricating grease contains a base oil on the basis of sustainable raw materials and / or with a proportion of more than 95% based on sustainable raw materials.

Composition according to at least one of claims 14 to 20, characterized in that the composition has a drop point of more than 200 ° C in accordance with DIN ISO 2176.

Use of the composition according to at least one of claims 14 to 22 for lubricating at least one transmission.

Use of the composition according to at least one of claims 14 to 22 for lubrication of lubrication points in homokinetic universal joints with a connecting shaft folding bellows made of thermoplastic polyether esters as connecting shaft folding bellows material.