Anti-friction varnish

Abstract

To improve an adhesion of a polymeric sliding layer on a substrate.SOLUTION: There is provided an anti-friction varnish comprising at least one organic binding agent, at least one solid lubricant and at least one adhesion promoter for improving the adhesion of a polymeric sliding layer (3) that can be produced from the anti-friction varnish on a substrate, wherein the at least one adhesion promoter includes a ligand, which connects the adhesion promoter to the organic binding agent or to the substrate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an anti-friction varnish comprising at least one organic binder, at least one solid lubricant, and at least one adhesion promoter for improving the adhesion of a polymer sliding layer that can be produced from the anti-friction varnish to a substrate.

[0002] The present invention further relates to a sliding bearing element comprising at least one metal layer on which a polymer sliding layer is arranged.

[0003] The present invention also relates to a method for manufacturing a sliding bearing element, comprising the steps of providing a substrate having at least one metal layer, applying an anti-friction varnish comprising at least one organic binder and at least one adhesion promoter to the metal layer, and curing the organic binder. The present invention further relates to the use of a corrosion inhibitor.

Background Art

[0004] Multilayer sliding bearing elements are usually used for the friction-reduced coupling of two mechanical elements, for example, two mechanical elements for the shaft of a rotating part such as a shaft. In this context, the use of polymer-based layers in sliding bearings is well described in the prior art. For example, a bearing element having a metal support, a bearing metal layer arranged thereon, and a polymer layer arranged thereon is known from European Patent Application Publication No. 1 717 469 (EP, A2) by the applicant. The polymer layer consists of a polyamide resin, molybdenum disulfide, and graphite.

[0005] Furthermore, the addition of adhesion promoters to anti-friction varnishes is known from the prior art. For example, former East German Patent No. 300 385 (DD, A7) describes an anti-friction varnish comprising an air-drying and / or oven-drying binder, fluoropolymer particles, and optionally pigments and / or dyes, a solvent, and a wetting agent. Using this varnish, an abrasion-resistant surface can be obtained with a low coefficient of friction, high abrasion resistance, high adhesion to the substrate material, anti-tack properties, and good water resistance. The anti-friction varnish contains a silane of the general formula R1-Si(OR)3, where R1 is an alkenyl group, a cycloalkenyl group, a cycloalkenyl alkyl group, or a (meth)acryloxyalkyl group, and R is an alkyl or alkoxyalkyl group having 1 to 5 C atoms. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] European Patent Application Publication No. 1717469 [Patent Document 2] Specification of Patent No. 300385, exclusive to the former East Germany [Overview of the project] [Problems that the invention aims to solve]

[0007] In view of the problem of the anti-friction varnish layer peeling off from the substrate, the present invention aims to improve sliding bearing elements equipped with anti-friction varnish.

[0008] The object of the present invention is achieved by the anti-friction varnish described above, wherein at least one adhesion promoter comprises at least one ligand that binds the adhesion promoter to an organic binder or substrate.

[0009] The object of the present invention is further achieved by the sliding bearing elements described earlier, which include polymer sliding bearing elements made from anti-friction varnish. [Means for solving the problem]

[0010] The object of the present invention is further achieved by the method described first, which involves applying the anti-friction varnish according to the present invention and bonding at least one adhesion promoter to the metal layer and / or organic binder.

[0011] Finally, the objectives of the present invention are also achieved by the use of a corrosion inhibitor as an adhesion promoter in a friction-reducing varnish for sliding bearing elements.

[0012] The advantages of the present invention are that the adhesion promoter itself can improve the adhesive strength of the polymer sliding layer on the substrate, and the bonding of the adhesion promoter to the substrate or organic binder allows the sliding layer produced from the anti-friction varnish to withstand higher mechanical loads without the risk of peeling of the sliding layer from the substrate. In this regard, according to the present method, the bonding of the adhesion promoter to the substrate and / or polymer binder can be established during the curing of the binder, thereby facilitating the production of the polymer sliding layer of the anti-friction varnish because no additional method steps are required to bond the adhesion promoter to the substrate or polymer binder. Furthermore, a corrosion inhibitor can be used as the adhesion promoter. Here, the additional functionality of "adhesion promoter" can be one that has already been introduced into the anti-friction varnish having the functionality of "corrosion prevention". In this way, the sliding bearing element can have improved adhesive strength on the substrate in addition to improved corrosion resistance.

[0013] To further improve the aforementioned effects, according to a modified embodiment of the present invention, the friction-reducing varnish may include both an adhesion promoter having a ligand that binds the adhesion promoter to a substrate, and an adhesion promoter having a ligand that binds the adhesion promoter to an organic binder.

[0014] According to a further embodiment of the present invention, the adhesion promoter may include both a ligand that binds the adhesion promoter to the substrate and a ligand that binds the adhesion promoter to an organic binder. In this way, the adhesion promoter can better bond the polymer slip layer to the substrate, resulting in a kind of crosslinking. This can further enhance at least some of the effects described above.

[0015] According to a modification of another embodiment of the present invention, it has been shown that ligands selected from the group consisting of azoles, silanes, thiols, orthophosphates, thiols, phosphonic acids, and sulfonic acids are particularly suitable for achieving the aforementioned effects regarding binding to a substrate.

[0016] According to a modification of another embodiment of the present invention, it has been shown that ligands selected from the group consisting of imides, amides, thioamides, thiocarbamides, carboxyls, silanes, siloxanes, and amines are particularly suitable for achieving the aforementioned effects on binding to polymers.

[0017] According to further embodiments of the present invention, - The azole is selected from the group consisting of dimercaptothiazole, toltriazole, 1,3,4-thiazole, benzotriazoles, especially benzotriazole-5-carboxylic acid, mercaptobenzotriazoles, imidazoles, especially benzimidazoles, and / or - The silane is epoxytrimethoxysilane, and / or - The orthophosphate can be trisodium phosphate.

[0018] According to a variant of another embodiment of the present invention, the proportion of the adhesion promoter in the total composition of the polymer sliding layer can be 0.2% by mass to 5% by mass. In the case of a proportion less than 0.2% by mass, no substantial improvement in the adhesion of the polymer sliding layer to the metal substrate will be observed. In the case of a proportion of the adhesion promoter exceeding 5% by mass, the proportion of the remaining components of the antifriction layer will decrease significantly, whereby further desired properties of the antifriction varnish, such as, for example, the cohesiveness of the layer itself, i.e., the embedding of the solid lubricant particles, or the reduction of the coefficient of friction, will be unduly impaired.

[0019] In a variant of a preferred embodiment of the present invention, particularly when the adhesion promoter is formed according to one of the variants of the foregoing embodiments, the organic binder is a polyimide, a polyamideimide, a polyester, or a phenolic resin.

[0020] According to a variant of an embodiment of the sliding bearing element of the present invention, since it has been observed that the aforementioned antifriction varnish exhibits the aforementioned effects particularly on a copper-containing metal layer, the metal layer can be made of an alloy containing copper.

[0021] Particularly when the adhesion promoter also acts as a corrosion inhibitor, it is particularly preferable that the polymer sliding layer is disposed on a lead-free sliding bearing element.

[0022] To better understand the present invention, it will be described in more detail with reference to the following figures. These figures are each very simplified schematic diagrams.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a side view of a multi-layer sliding bearing element.

Modes for Carrying Out the Invention

[0024] First, note that in the various embodiments described, the same part is given the same reference number and / or the same component designation, and the disclosures contained throughout this description can be similarly applied to equivalent parts having the same reference number and / or the same component designation. Furthermore, the specifications of the top, bottom, side, etc., selected in this description refer to the directly described and depicted figures, and if the position is changed, the specifications of these positions will similarly apply to the new position.

[0025] The indication of alloy composition should be understood to include the usual impurities found in raw materials used on an industrial scale. However, in the context of this invention, it is possible to use pure metals and / or ultrapure metals. Furthermore, unless otherwise specified, composition should be understood to be expressed in mass percent.

[0026] Figure 1 shows a sliding bearing element 1 (sometimes called a multilayer sliding bearing element) in the form of a sliding bearing half-shell. The figure shows a modified two-layer sliding bearing element 1 consisting of a support layer 2 and a sliding layer 3, where the sliding layer 3 is located on the front side 4 (radially inward) of the sliding bearing element 1, facing the component to be supported.

[0027] In some cases, a bearing metal layer 5 can be placed between the sliding layer 3 and the support layer 2, as shown by the dashed line in Figure 1.

[0028] For example, the basic structure of a sliding bearing element 1, such as that used in an internal combustion engine, is known from the prior art, so further explanation can be omitted. However, it should be noted that further layers, namely, an adhesion promoter layer and / or a diffusion barrier layer, can be placed between the metal bearing layer 5 and the supporting metal layer.

[0029] In the context of the present invention, the multilayer sliding bearing 1 may be designed differently, for example as a bearing bush, as shown by the dashed line in Figure 1. Similarly, designs such as thrust rings and axially extending sliding shoes are also possible.

[0030] The sliding layer 3 is preferably placed on a metal layer of the sliding bearing element 1, which contains copper. In particular, the sliding layer is placed directly on this layer.

[0031] In this context, "containing copper" refers to alloys containing copper as an alloying component, copper-based alloys in which copper forms a matrix and other phases of the copper-based alloy are encapsulated or arranged within it, and layers formed solely of copper. However, it is preferable that the sliding layer 3 is (directly) placed on and / or bonded to the copper-based alloy.

[0032] Furthermore, it is preferable that all layers of the sliding bearing element 1 are formed without lead. In this context, “lead-free” means that these layers are preferably lead-free. However, at least one of these layers may contain the maximum percentage of lead in the amount of impurities typically present in the elements used to manufacture each layer of the sliding bearing element 1. This percentage of lead may, for example, originate from recycled metal. Typically, the aforementioned percentage of lead in each layer of the sliding bearing element 1 is not higher than 0.1 mass%. In any case, in any modification of the preferred embodiment of the sliding bearing element 1, no additional lead is added as an alloy component.

[0033] The support layer 2 may be made of steel, but it may also be made of another material that provides the necessary structural strength to the sliding bearing element 1. Such materials are known from the prior art. For example, the support layer 2 may be made of copper bronze.

[0034] If the sliding layer 3 is not directly placed on the support layer 3, the bearing metal layer 5 may be a copper-containing layer on which the sliding layer 3 is placed.

[0035] Furthermore, it is possible to place an additional sliding layer between the bearing metal layer 5 and the sliding layer 3. This additional sliding layer is preferably a metal sliding layer containing copper. In this case, the sliding layer 3 placed on top of the additional sliding layer may (or may) function as a break-in layer.

[0036] Alloys and / or materials known from the relevant prior art may be used for the bearing metal layer 5 and the intermediate layer, and in this regard, corresponding references are made to them.

[0037] The sliding layer 3 is a polymer-based layer formed from a friction-reducing varnish.

[0038] Anti-friction varnish can be in solid or, preferably, liquid form and can be applied to the respective substrate. Application methods are well known and do not require further explanation. Anti-friction varnish can be applied, for example, by coating, spraying, or dipping.

[0039] The anti-friction varnish comprises at least one organic binder, at least one solid lubricant, and at least one adhesion promoter for improving the adhesion of the polymer lubrication layer 3, which can be produced from the anti-friction varnish, to the substrate. Furthermore, the anti-friction varnish may contain at least one additional component, such as hard particles, metal particles, at least one solvent, or a colorant.

[0040] The organic binder or polymer base is preferably polyimide, polyamide-imide, polyester, or phenolic resin. However, other organic-based organic binders, such as epoxides or polybenzimidazole (PBI), can also be used. Similarly, mixtures of at least two of the aforementioned polymers, or modifications of these polymers, can also be used as organic binders.

[0041] In anti-friction varnishes, the organic binder exists in an uncured state (and preferably in a dissolved state) as a monomer, or generally as a precursor of a polymer. A polymer is formed during or by curing.

[0042] Polyimide polymers can be selected from the group consisting of, for example, polyimide (PI), polyscinimide (PSI), polybismaleimide (PBMI), polybenzimidazole (PBI), polyoxadiazobenzimidazole (PBO), and polyimide sulfone (PISO), or mixtures thereof.

[0043] Preferably, the polymer is a polyamide-imide. The polyamide-imide may contain at least partially aromatic groups, or it may be a fully aromatic polyamide-imide.

[0044] The proportion of polymer binder in the polymer layer that can be produced from the anti-friction varnish, particularly the slip layer 3, is preferably selected from a range of 25% by mass at the lower limit and 50% by mass at the upper limit, and particularly from a range of 30% by mass at the lower limit and 45% by mass at the upper limit. In particular, it is preferable that the proportion of binder in the polymer layer be 37% by mass.

[0045] It should be noted that the solvent is removed by the curing of the anti-friction varnish and / or during curing. Therefore, if the anti-friction varnish contains a solvent, its composition may differ from that of the polymer layer. In this case, the proportion of solvent in the anti-friction varnish must be considered.

[0046] In this regard, it should be noted that all disclosures relating to the composition of the polymer layer and / or anti-friction varnish should naturally be understood as such that the sum of the quantitative proportions of all components of the polymer layer and / or anti-friction varnish equals 100% by mass. Therefore, the polymer layer and / or anti-friction varnish may also have compositions selected from the range mentioned herein.

[0047] Solid lubricant particles can be selected from the group consisting of graphite, MoS2, WS2, Sn, SnS and SnS2, ZnS, ZnS2, hexagonal BN, Sn alloy, CF2, PbF2, PTFE, etc. Mixtures of two or more different solid lubricant particles can also be used. In principle, these solid lubricants are already known from the prior art to a sufficient extent for this purpose.

[0048] The total proportion of solid lubricant particles in the polymer layer, particularly the sliding layer 3, that can be produced from the anti-friction varnish can be selected from a range of 25% by mass at the lower limit and 60% by mass at the upper limit, and particularly from a range of 40% by mass at the lower limit and 60% by mass at the upper limit. In particular, it is preferable that the total proportion of solid lubricant particles in the polymer layer is 50% by mass to 55% by mass.

[0049] The solid lubricant particles can have a maximum particle size D90 of 40 μm.

[0050] In this context, the maximum particle diameter is understood to be the particle dimension that is the largest compared to other dimensions of the same particle. Therefore, the maximum dimension can also be understood as the diameter of the sphere that completely encloses each particle.

[0051] In particular, solid lubricant particles can have a particle size distribution (D50) of 3 μm to 15 μm, which can be determined by sieve analysis.

[0052] In a modified version of the preferred embodiment, the anti-friction varnish, and consequently the polymer layer, contains graphite and MoS2 as solid lubricant particles. In this regard, the proportion of graphite in the polymer layer can be selected from a range of 0.1% by mass to 20% by mass, particularly from a range of 5% by mass to 15% by mass. It is particularly preferred that the proportion of graphite in the polymer layer be 8% by mass. MoS2 forms the remainder of the total proportion of solid lubricant in the polymer layer.

[0053] The polymer layer and / or anti-friction varnish may contain hard particles to adjust the hardness of the polymer layer. These hard particles may be metal oxide particles, such as CrO3, Fe3O4, ZnO, CdO, Al2O3, SiO2 2、 The following can be selected from the group consisting of MnO, TiO2, mixed oxide particles such as bismuth vanadate (BiVO4), chromium antimony rutile, clay, talc, aluminum silicate such as mullite, magnesium silicate such as amosite, antphyllite, chrysotile, carbides such as SiC, CaC2, Mo2C, WC, metal particles such as Al, Ag, Sn, Zn, Ag, Ba, bronze, Cd, Co, Cu, In, alloy particles of these metals, metal nitrides such as Si3N4, AlN, Fe3P, metal borides such as Fe2B, Ni2B, FeB, BaSO4, chlorinated bicarbonate, fluoride such as CaF2, metal oxyfluoride, crocidolite, tremolite, silicides, thiophosphates such as zinc thiophosphate, etc.

[0054] A mixture of different additives and / or hard materials, for example, a mixture of two, three, four or more different additives and / or hard materials, can also be used.

[0055] The proportion of hard particles in the polymer layer can be selected from a range having a lower limit of 1% by mass and an upper limit of 20% by mass, and in particular from a range having a lower limit of 1% by mass and an upper limit of 5% by mass.

[0056] The solvents that may be present in the anti-friction varnish as needed can be selected from the group including and / or the group comprising xylene, dimethylformamide, methyl ethyl ketone, γ-butyrolactone, dimethylacetamide, N-methyl-2-pyrrolidone, 1-butylpyrrolidine-2-one, etc. A mixture of at least two different solvents may also be used.

[0057] The proportion of at least one solvent in the anti-friction varnish can be selected from a range having a lower limit of 50% by mass and an upper limit of 80% by mass, and in particular from a range having a lower limit of 60% by mass and an upper limit of 70% by mass. Preferably, the proportion of solvent in the anti-friction varnish is 65% by mass.

[0058] However, the anti-friction varnish (and therefore the polymer layer as well) may contain further components such as fibers and metal plates. The proportion of these further components is between 0.1% by mass and 20% by mass.

[0059] As described above, the anti-friction varnish, and by extension the polymer layer produced from the anti-friction varnish, particularly the slip layer 3, contains at least one adhesion promoter. The adhesion promoter is intended to bond to an organic polymer binder or to a (metallic) substrate to which the anti-friction varnish is applied. In particular, this bond is formed in the form of a coordination bond (donor-acceptor bond) with respect to the bond to the polymer binder and the bond to the substrate. However, other bonds, such as a covalent bond to the polymer binder, are also possible. For this purpose, at least one adhesion promoter contains a corresponding ligand, which will be further described below.

[0060] In this context, it should be noted that ligands can be understood as compounds themselves, as well as specific chemical groups (sometimes called "reactive groups") within a molecule of an adhesion promoter that reacts or can react with a binder or substrate. For example, the compound "benzotriazole" may contain the ligand "carboxylic acid" which forms a bond to the polymer. In this case, the adhesion promoter is benzotriazole-5-carboxylic acid. Similarly, the compound "undecane" may have the ligand "thiol" as an adhesion promoter and the ligand "carboxyl" as a bond to the binder, in which case the added substance is 11-mercaptoundecanoic acid. When the ligand is a reactive group, the carrier molecule supporting the ligand can be an organic compound with a molar mass of up to 200 g / mol, preferably up to 150 g / mol, and particularly up to 100 g / mol. The lower limit of these ranges is preferably 20 g / mol. The carrier molecule can be, for example, phenols, alkanes, such as butane and undecane.

[0061] According to one aspect of the present invention, the friction-reducing varnish may include both an adhesion promoter having a ligand, wherein the ligand binds the adhesion promoter to a substrate, and an adhesion promoter having a ligand, wherein the ligand binds the adhesion promoter to an organic binder. Therefore, the polymer layer is bound to the substrate on the one hand and to the binder (i.e., the binder molecule) on the other hand, but no continuous binding of the binder molecule to the substrate is provided.

[0062] To achieve this, according to a further embodiment of the present invention, the adhesion promoter can be provided to carry at least two different ligands, one of which binds to the substrate and the other ligands to the binder. Thus, direct bonding of the binder to the substrate via the adhesion promoter can be achieved.

[0063] The proportion of adhesion promoter in the total composition of the polymer layer obtained from the anti-friction varnish (slip layer 3) (and / or the total proportion of adhesion promoters if there are multiple adhesion promoters) is preferably 0.2% to 5% by mass, and more particularly 0.5% to 2.5% by mass. For example, the proportion of adhesion promoter in the total composition of the polymer layer can be 1.8% to 2.2% by mass. The proportion of adhesion promoter in the anti-friction varnish containing the solvent can be calculated from these values, taking into account the proportion of the solvent. For this purpose, the composition of the polymer layer obtained from the anti-friction varnish is used as a reference, in accordance with the disclosure herein. This composition must be in total proportion of 100% by mass in the first step. Next, when the proportion of the solvent is added to this composition, the proportion of the individual components of the predetermined composition in the anti-friction varnish is reduced by the solvent in proportion to the proportion of the solvent. This is known to those skilled in the art and therefore no further explanation is needed.

[0064] According to a modified embodiment of the present invention, the ligand (i.e., in this case, a reactive group) that binds the adhesion promoter to the substrate is selected from the group consisting of azoles, silanes, thiols, orthophosphates, thiols, phosphonic acids, and sulfonic acids, and / or the ligand (i.e., in this case, a reactive group) that binds the adhesion promoter to the polymer is selected from the group consisting of imides, amides, thioamides, thiocarbamides, carboxyls, silanes, amines, vinyls, methacrylates, epoxides, carbamides, titanates, and zirconates.

[0065] The azole can be selected from the group including or comprising dimercaptothiazole, toltriazole, 1,2,4-thiazole, benzotriazoles, particularly benzotriazole-5-carboxylic acid, mercaptobenzotriazoles, imidazoles, particularly benzimidazoles.

[0066] The silane can be epoxytrimethoxysilane.

[0067] Orthophosphate can be trisodium phosphate.

[0068] For example, the adhesion promoter may be 5-amino-1,3,4-thiadiazole-2-thiol and / or 3-aminopropyltriethoxysilane and / or (benzothiazole-2-ylthio)succinylic acid and / or 11-mercaptoundecanoic acid and / or 2-(2H-benzotriazole-2-yl)-4,6-bis-(1-phenylethyl-1-methyl)phenol and / or benzotriazole-5-carboxylic acid and / or epoxytrimethoxysilane and / or 5-amino-5-mercapto-1,3,4-thiazole and / or benzotriazole-1-carboxamide and / or 5-benzotriazolecarboxylic acid.

[0069] Table 1 shows some of the compositions tested in the course of the present invention. It should be noted that corresponding tests were carried out using the ligands mentioned further, but their reproducibility is beyond the scope of this description.

[0070] All of these compositions showed improved adhesion in a bearing test apparatus under vibrating relative motion and / or increased load compared to the same compositions without adhesion promoters.

[0071] All quantitative percentages should be understood as being in mass percent. The compositional indication refers to the composition of the polymer layer derived from the anti-friction varnish, i.e., without the solvent.

[0072] [Table 1]

[0073] To manufacture a sliding bearing element, in the first step, a single-layer or multi-layer substrate is provided. This can be manufactured using a method known in general (in the sliding bearing industry). Subsequently, an anti-friction varnish is applied to the substrate, for example, using one of the above methods. After application of an adhesion promoter, it is cured. This can be done, for example, by heat treatment, UV light, infrared irradiation, etc. The curing of the anti-friction varnish itself is known to those skilled in the art. By curing, the polymer layer resulting from the anti-friction varnish is bonded to the substrate, particularly the metal layer, and / or to an organic binder.

[0074] The present invention also relates to the use of corrosion inhibitors as adhesion promoters in anti-friction varnishes for sliding bearing elements, wherein the corrosion inhibitor is selected from the above ligands.

[0075] The exemplary embodiments illustrate or describe variations of possible embodiments, and in this regard, it should be noted that the present invention is not limited to variations of these specific illustrated embodiments, but rather various combinations of variations of the individual embodiments are possible, and the possibilities of such variations through teachings of the technical operation provided by the present invention are within the scope of those skilled in the art.

[0076] Finally, as a formal issue, it should be noted that, in order to facilitate understanding of the sliding bearing element 1, it is not necessarily drawn to scale. Some embodiments of the present invention are shown below. [Embodiment 1] A friction-reducing varnish comprising at least one organic binder, at least one solid lubricant, and at least one adhesion promoter for improving the adhesion of a polymer lubrication layer (3) that can be produced from the friction-reducing varnish to a substrate, wherein the at least one adhesion promoter comprises a ligand that binds the adhesion promoter to the organic binder or to the substrate. [Embodiment 2] The friction-reducing varnish according to Embodiment 1, characterized in that it includes both an adhesion promoter having a ligand, wherein the ligand binds the adhesion promoter to a substrate, and an adhesion promoter having a ligand, wherein the ligand binds the adhesion promoter to an organic binder. [Embodiment 3] The friction-reducing varnish according to Embodiment 2, characterized in that the adhesion promoter includes both a ligand that bonds the adhesion promoter to the substrate and a ligand that bonds the adhesion promoter to an organic binder. [Embodiment 4] The anti-friction varnish according to any one of Embodiments 1 to 3, characterized in that the ligand used to bond the adhesion promoter to the substrate is selected from the group consisting of azoles, silanes, thiols, orthophosphates, thiols, phosphonic acids, and sulfonic acids. [Embodiment 5] The anti-friction varnish according to any one of Embodiments 1 to 4, characterized in that the ligand used to bond the adhesion promoter to the polymer is selected from the group consisting of imides, amides, thioamides, thiocarbamides, carboxyls, silanes, siloxanes, and amines. [Embodiment 6] The anti-friction varnish according to Embodiment 4, characterized in that the azole is selected from the group consisting of dimercaptothiazole, toltriazole, 1,3,4-thiazole, benzotriazole, particularly benzotriazole-5-carboxylic acid, mercaptobenzotriazoles, imidazoles, particularly benzimidazoles. [Embodiment 7] The anti-friction varnish according to Embodiment 4, characterized in that the silane is epoxytrimethoxysilane. [Embodiment 8] The anti-friction varnish according to Embodiment 4, characterized in that the orthophosphate is trisodium phosphate. [Embodiment 9] The anti-friction varnish according to any one of Embodiments 1 to 8, characterized in that the organic binder is polyimide, polyamideimide, polyester, or phenolic resin. [Embodiment 10] A sliding bearing element (1) comprising at least one metal layer, wherein a polymer sliding layer (3) is disposed on the metal layer, characterized in that the polymer sliding layer (3) is made from an anti-friction varnish described in any one of embodiments 1 to 9. [Embodiment 11] The sliding bearing element according to Embodiment 10, characterized in that the proportion of the adhesion promoter in the total composition of the polymer sliding layer is 0.2% to 5% by mass, particularly 0.5% to 2.5% by mass. [Embodiment 12] A sliding bearing element (1) according to embodiment 10 or 11, characterized in that the metal layer is an alloy containing copper. [Embodiment 13] A sliding bearing element (1) according to any one of embodiments 10 to 12, characterized in that all layers of the sliding bearing element are lead-free. [Embodiment 14] A method for manufacturing a sliding bearing element (1), - A step of providing a substrate having at least one metal layer, - A step of applying a friction-reducing varnish containing at least one organic binder and at least one adhesion promoter to a metal layer, - A step of curing the organic binder, Includes, A method for manufacturing a sliding bearing element, characterized in that the friction-reducing varnish described in any one of embodiments 1 to 11 is applied as the friction-reducing varnish, and at least one type of binder is bonded to the metal layer and / or the organic binder. [Embodiment 15] Use of a corrosion inhibitor as an adhesion promoter in a friction-reducing varnish for a sliding bearing element (1). [Explanation of symbols]

[0077] 1. Sliding bearing element 2 Support layer 3. Slip layer 4. Front side 5. Bearing metal layer

Claims

1. A friction-reducing varnish comprising at least one organic binder, at least one solid lubricant, and at least one adhesion promoter for improving the adhesion of a polymer lubrication layer (3) that can be produced from the friction-reducing varnish to a substrate, The at least one adhesion promoter is 5-amino-1,3,4-thiadiazole-2-thiol, 3-aminopropyltriethoxysilane, (Benzothiazole-2-ylthio) succinyl acid, 11-mercaptoundecanoic acid, 2-(2H-benzotriazol-2-yl)-4,6-bis-(1-phenylethyl-1-methyl)phenol, 5-Benzimidazole carboxylic acid, Epoxytrimethoxysilane, Benzotriazole-5-carboxylic acid, and Benzotriazole-1-carboxamide, A friction-reducing varnish characterized by being selected from the group consisting of the following.

2. The anti-friction varnish according to claim 1, characterized in that the organic binder is polyimide, polyamideimide, polyester, or phenolic resin.

3. A sliding bearing element (1) comprising at least one metal layer, wherein a polymer sliding layer (3) is disposed on the metal layer, characterized in that the polymer sliding layer (3) is made from the anti-friction varnish described in claim 1 or 2.

4. The sliding bearing element according to claim 3, characterized in that the proportion of the adhesion promoter in the total composition of the polymer sliding layer is 0.2% by mass to 5% by mass.

5. The sliding bearing element (1) according to claim 3 or 4, characterized in that the metal layer is an alloy containing copper.

6. A sliding bearing element (1) according to any one of claims 3 to 5, characterized in that all layers of the sliding bearing element are lead-free.

7. A method for manufacturing a sliding bearing element (1), - A step of providing a substrate having at least one type of metal layer, - A step of applying a friction-reducing varnish containing at least one organic binder and at least one adhesion promoter to a metal layer, - A step of curing the organic binder, Includes, A method for manufacturing a sliding bearing element, characterized in that the friction-reducing varnish described in any one of claims 1 to 4 is applied as the friction-reducing varnish, and at least one type of binder is bonded to the metal layer and / or the organic binder.

8. Use of a corrosion inhibitor as the adhesion promoter in the anti-friction varnish for the sliding bearing element (1) according to claim 3.

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