Anti-friction lacquer
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SURTEC INT
- Filing Date
- 2025-09-16
- Publication Date
- 2026-08-06
Smart Images
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Abstract
Description
[0001] Lubricant
[0002] The invention relates to a sliding coating, a sliding coating layer produced from the sliding coating, a powder coating based on the components of the sliding coating, and their use for lubricating a tribological system, in particular a tribological system in the automotive sector.
[0003] Dry film lubricants are functional coatings designed to minimize friction between surfaces. They are an essential element in a wide variety of applications, as they increase the efficiency and longevity of machinery and equipment. In industrial environments, where machines often operate under extreme conditions, high friction can lead to increased wear. This can significantly shorten the machine's lifespan and result in costly repairs or even machine failure. By using dry film lubricants, friction and wear can be minimized, thus extending the machine's service life. This not only leads to cost savings but can also improve workplace safety by reducing the risk of machine breakdowns and related accidents.
[0004] Lubricating coatings can be used to coat metallic and non-metallic surfaces. An important application for these coatings is on elastomers, such as those used in seals. Elastomers are characterized by their high elastic properties. They can deform under stress and then return to their original shape. This makes them suitable for a wide variety of applications, such as seals that require a durable seal against air, water, and other substances. However, the use of elastic materials also generates friction, which can lead to wear and a reduced service life. Coating with lubricating coatings can reduce this friction and thus minimize wear.
[0005] For example, door seals typically contain a base profile made of an elastic material such as EPDM (ethylene propylene diene monomer rubber). Door seals are often flocked with a layer of flock material, which provides a soft surface and improves the sealing properties. For this, a layer of flock, i.e., short fibers, is applied to the base profile. The seal material is then applied to the flocked surface.
[0006] A sliding lacquer is applied to reduce friction between the seal and the door or window frame. This facilitates opening and closing and extends the seal's service life. Good wetting properties of the lacquer on the flock fibers are advantageous. In particular, the most uniform and complete wetting of the fibers possible is desirable. In some designs, however, it may be advantageous for the lacquer layer to be thicker at the fiber tip.
[0007] Dry film lubricants can contain a variety of components, depending on the specific application and desired properties. The main components of dry film lubricants are solid lubricants and binders. The solid lubricants reduce friction and wear, while the binders serve to hold the solid lubricant on the surface. Polytetrafluoroethylene (PTFE) is used as a solid lubricant in many dry film lubricants due to its very high non-stick and sliding properties. PTFE is known for its excellent lubricating effect, resulting from very low and constant coefficients of friction even under high loads. It effectively prevents stick-slip and exhibits good stability even under high shear stress. Furthermore, it has excellent chemical inertness and very favorable toxicological properties due to its good chemical and thermal resistance.
[0008] However, the use of PTFE is problematic from an environmental perspective. Disposing of PTFE-containing materials is difficult due to PTFE's high stability. Furthermore, the production and degradation of PTFE-containing materials generate low-molecular-weight, highly fluorinated substances that can accumulate in plants and animals and may be toxic. Additionally, PTFE can deform under pressure, which is problematic in certain applications.
[0009] The object of the present invention is to provide a sliding coating that exhibits good sliding properties and high wear resistance, and with which the disadvantages of the prior art can be at least partially eliminated. The sliding coating should be suitable for coating elastomers, in particular elastic flock material, and should be PTFE-free, making it a more environmentally friendly and safer alternative to conventional PTFE-containing sliding coatings.
[0010] This task is solved by a comprehensive sliding coating
[0011] a1) Talc in an amount of 2 wt.% to 15 wt.%, preferably 3 wt.% to 13 wt.%, in particular 4 wt.% to 11 wt.%, based on the total weight of the sliding lacquer, a2) Graphite in an amount of 0.5 wt.% to 10 wt.%, preferably 0.5 wt.% to 6 wt.%, more preferably 0.5 wt.% to 4 wt.%, in particular 0.5 wt.% to 2 wt.%, based on the total weight of the sliding lacquer,
[0012] a3) Polymethylurea in an amount of 0.5 wt.% to 10 wt.%, preferably 2 wt.% to 9 wt.%, more preferably 3 wt.% to 8 wt.%, in particular 3 wt.% to 7 wt.%, based on the total weight of the sliding varnish,
[0013] a4) Boron nitride in an amount of 0.8 wt.% to 5 wt.%, preferably 0.8 wt.% to 4 wt.%, more preferably 0.8 wt.% to 3 wt.%, in particular 0.8 wt.% to 2 wt.%, based on the total weight of the sliding lacquer, b) at least one binder in an amount of 5 wt.% to 60 wt.%, more preferably 10 wt.% to 50 wt.%, in particular 12 wt.% to 35 wt.%, based on the total weight of the sliding lacquer, and
[0014] c) at least one solvent in an amount of 50 wt.% to 80 wt.%, preferably 60 wt.% to 80 wt.%, in particular 65 wt.% to 80 wt.%, based on the total weight of the sliding varnish.
[0015] The sliding coating according to the invention can do without PTFE and yet exhibits good sliding properties and high wear resistance. Furthermore, it shows better compression set properties than a sliding coating based on PTFE as a solid lubricant.
[0016] The sliding varnish according to the invention contains the solid lubricants talc (a1), graphite (a2), polymethyl urea (a3) and boron nitride (a4) together. It therefore contains a solid lubricant mixture.
[0017] Talc a1)
[0018] The sliding coating according to the invention contains talc as a solid lubricant. Talc is a layered silicate with the chemical composition Mg3[(OH)2|Si4O ]. Chemically speaking, talc is therefore a magnesium silicate hydrate.
[0019] Preferably, the talc has a Mohs hardness of 1 to 2 and / or a density of 2.58 g / cm³. 3 up to 2.83 g / cm³ 3 According to the invention, the amount of talc, based on the total weight of the sliding lacquer, is from 2 wt.% to 15 wt.%, preferably from 3 wt.% to 13 wt.%, and in particular from 4 wt.% to 11 wt.%.
[0020] In a preferred embodiment of the invention, the amount of talc, based on the total weight of the solid lubricants a1), a2), a3) and a4) taken together, is from 3 wt.% to 80 wt.%, preferably from 5 wt.% to 80 wt.%, more preferably from 10 wt.% to 70 wt.%, more preferably from 30 wt.% to 70 wt.%, and in particular from 50 wt.% to 60 wt.%.
[0021] Preferably, the talc has a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 1 pm to 10 pm, in particular of 2 pm to 6 pm.
[0022] Preferably, the talc has a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 5 pm to 15 pm, particularly of 5 pm to 10 pm.
[0023] Graphite a2)
[0024] The sliding coating according to the invention contains graphite as a solid lubricant. Preferably, the graphite has a hexagonal structure. In this structure, each layer is connected to the adjacent layer by weak van der Waals forces, which allows the layers to slide easily over one another.
[0025] Preferably, the graphite has a Mohs hardness of 1 to 2 and / or a density of 2.1 g / cm³. 3 up to 2.3 g / cm³ 3 on.
[0026] According to the invention, the amount of graphite, based on the total weight of the sliding varnish, is from 0.5 wt.% to 10 wt.%, preferably from 0.5 wt.% to 6 wt.%, more preferably from 0.5 wt.% to 4 wt.%, and in particular from 0.5 wt.% to 2 wt.%.
[0027] In a preferred embodiment of the invention, the amount of graphite, based on the total weight of the solid lubricants a1), a2), a3) and a4) taken together, is from 3 wt.% to 80 wt.%, preferably from 3 wt.% to 60 wt.%, more preferably from 3 wt.% to 30 wt.%, and even more preferably from 3 wt.% to 15 wt.%, and in particular from 3 wt.% to 10 wt.%. Preferably, the graphite has a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably from 1 pm to 10 pm, and in particular from 2 pm to 6 pm.
[0028] Preferably, the graphite has a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 5 pm to 15 pm, in particular of 5 pm to 10 pm.
[0029] Polymethylurea a3)
[0030] The sliding varnish according to the invention contains polymethyl urea as a solid lubricant.
[0031] Polymethylurea is a polymer that can be produced by reacting urea with formaldehyde. A preferred polymethylurea has the CAS number 9011-05-6. The figures below show typical reaction steps and intermediates for the preparation of an exemplary polymethylurea.
[0032]
[0033] The polymethylurea can be uncrosslinked, partially crosslinked, or fully crosslinked. Preferably, the polymethylurea is a thermoset. Also preferably, the polymethylurea is fully crosslinked. Also preferably, the polymethylurea has a proportion of extractable components by methanol according to ISO 6427:2014-08 of less than 10 wt.%, preferably from 0 wt.% to 10 wt.%.
[0034] The following is an example of a structural section of a fully cross-linked polymethylurea.
[0035]
[0036] The degree of cross-linking can be adjusted by specifically adjusting the stoichiometric ratios of the reactants and the reaction conditions.
[0037] In a preferred embodiment, the polymethylurea has a density at 23°C and 1.013 bar in the range of 1.4 to 1.5 g / cm³. 3 on.
[0038] Preferably, the polymethylurea has an OH number, determined according to ISO 4629-1:2016, of less than 9 mg KOH / g, particularly preferably from 0.33 mg KOH / g to 9 mg KOH / g. The OH content of the polymethylurea can be calculated from the OH number. Preferably, the polymethylurea has an OH content of less than 0.3 wt.%, for example, from 0.01 wt.% to 0.3 wt.%, based on the total weight of the polymethylurea. These OH contents and OH numbers are advantageous because they reduce undesirable side reactions during crosslinking of the lubricant. In particular, these values have a beneficial effect on the crosslinking density of the lubricant.
[0039] In a preferred embodiment, the polymethylurea has a Mohs hardness of 3 to 4.
[0040] According to the invention, the amount of polymethyl urea, based on the total weight of the sliding varnish, is from 0.5 wt.% to 10 wt.%, preferably from 2 wt.% to 9 wt.%, more preferably from 3 wt.% to 8 wt.%, in particular from 3 wt.% to 7 wt.%.
[0041] In a preferred embodiment, the amount of polymethylurea, based on the total weight of the solid lubricants a1), a2), a3) and a4) taken together, is from 1.5 wt.% to 70 wt.%, preferably from 5 wt.% to 60 wt.%, more preferably from 15 wt.% to 50 wt.%, and more preferably from 25 wt.% to 45 wt.%, particularly from 25 wt.% to 40 wt.%.
[0042] In a further preferred embodiment, the polymethylurea has a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 1 pm to 10 pm, more preferably of 2 pm to 7 pm, in particular of 2 pm to 6 pm.
[0043] The polymethylurea preferably has a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 5 pm to 15 pm, more preferably of 5 pm to 13 pm, in particular of 5 pm to 10 pm.
[0044] Boron nitride a4)
[0045] According to the invention, the solid lubricant mixture contains boron nitride as a solid lubricant.
[0046] Boron nitride has the chemical formula BN. It preferably exhibits a hexagonal crystal structure.
[0047] According to the invention, the amount of boron nitride, based on the total weight of the sliding varnish, is from 0.8 wt.% to 5 wt.%, preferably from 0.8 wt.% to 4 wt.%, more preferably from 0.8 wt.% to 3 wt.%, and in particular from 0.8 wt.% to 2 wt.%.
[0048] According to the invention, it was found that the sliding lacquer exhibits good properties even with a small proportion of boron nitride. This is advantageous because boron nitride is expensive.
[0049] Preferably, the amount of boron nitride, based on the total weight of the solid lubricants a1), a2), a3) and a4) taken together, is from 3 wt.% to 70 wt.%, preferably from 3 wt.% to 40 wt.%, even more preferably from 3 wt.% to 25 wt.%, in particular from 3 wt.% to 10 wt.%.
[0050] Preferably, the boron nitride has a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 1 pm to 10 pm, in particular of 2 pm to 6 pm.
[0051] Preferably, the boron nitride has a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 5 pm to 15 pm, and particularly of 5 pm to 11 pm. Furthermore, the talc, graphite, polymethyl urea, and / or the boron nitride, independently of one another, have a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 1 pm to 10 pm, and particularly of 2 pm to 6 pm.
[0052] Preferably, the talc, graphite, polymethyl urea and / or boron nitride independently exhibit a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 5 pm to 15 pm, particularly of 5 pm to 10 pm.
[0053] solid lubricant mixture
[0054] According to the invention, the sliding varnish contains talc, graphite, polymethyl urea, and boron nitride, which act as solid lubricants. The sliding varnish therefore preferably contains a solid lubricant mixture comprising talc, graphite, polymethyl urea, and boron nitride.
[0055] The solid lubricant mixture includes
[0056] a1) Talc in an amount of 2 wt.% to 15 wt.%, preferably 3 wt.% to 13 wt.%, in particular 4 wt.% to 11 wt.%, based on the total weight of the sliding varnish,
[0057] a2) Graphite in an amount of 0.5 wt.% to 10 wt.%, preferably 0.5 wt.% to 6 wt.%, more preferably 0.5 wt.% to 4 wt.%, in particular 0.5 wt.% to 2 wt.%, based on the total weight of the sliding varnish,
[0058] a3) Polymethylurea in an amount of 0.5 wt.% to 10 wt.%, preferably 2 wt.% to 9 wt.%, more preferably 3 wt.% to 8 wt.%, in particular 3 wt.% to 7 wt.%, based on the total weight of the sliding varnish,
[0059] a4) Boron nitride in an amount of 0.8 wt.% to 5 wt.%, preferably 0.8 wt.% to 4 wt.%, more preferably 0.8 wt.% to 3 wt.%, in particular 0.8 wt.% to 2 wt.%, based on the total weight of the sliding varnish.
[0060] In a preferred embodiment, the amount of the solid lubricant mixture is 4 wt.% to 40 wt.%, more preferably 4 wt.% to 30 wt.%, and even more preferably 5 wt.% to 30 wt.%, particularly 10 wt.% to 20 wt.%, based on the total weight of the sliding varnish. In a preferred embodiment of the invention, the combined amount of talc, graphite, polymethyl urea, and boron nitride is 4 wt.% to 40 wt.%, more preferably 4 wt.% to 30 wt.%, and even more preferably 5 wt.% to 30 wt.%, particularly 10 wt.% to 20 wt.%, based on the total weight of the sliding varnish.
[0061] In addition to talc, graphite, polymethyl urea, and boron nitride, the solid lubricant mixture may contain other solid lubricants. For example, the sliding varnish may contain at least one other solid lubricant selected from the group consisting of polytetrafluoroethylene (PTFE), molybdenum disulfide, graphene (hexagonal), tin(IV) sulfide, zinc(II) sulfide, tungsten disulfide, metal sulfide, calcium phosphate, silicate, layered silicate, mica, and mixtures thereof.
[0062] In a preferred embodiment, the sliding varnish comprises at least one further solid lubricant selected from the group consisting of molybdenum disulfide, graphene (hexagonal), tin(IV) sulfide, zinc(II) sulfide, tungsten disulfide, metal sulfide, calcium phosphate, silicate and layered silicate, mica and mixtures thereof.
[0063] If present, the amount of at least one additional solid lubricant, preferably selected from the group consisting of polytetrafluoroethylene (PTFE), molybdenum disulfide, graphene (hexagonal), tin(IV) sulfide, zinc(II) sulfide, tungsten disulfide, metal sulfide, calcium phosphate, silicate and layered silicate, mica and mixtures thereof, in particular selected from the group consisting of molybdenum disulfide, graphene (hexagonal), tin(IV) sulfide, zinc(II) sulfide, tungsten disulfide, metal sulfide, calcium phosphate, silicate and layered silicate, mica and mixtures thereof, is from 0.5 wt.% to 10 wt.%, preferably from 1 wt.% to 8 wt.%, based on the total weight of the sliding varnish.
[0064] The solid lubricant mixture preferably has a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 1 pm to 10 pm, in particular of 2 pm to 6 pm.
[0065] Further preferably, the solid lubricant mixture has a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 5 pm to 15 pm, in particular of 5 pm to 10 pm.
[0066] Binder b) According to the invention, the sliding coating contains at least one binder b). Binders are substances that are able to at least partially encapsulate the solid lubricants contained in the sliding coating and to bond them to each other and, optionally, to a substrate. An advantage of using a binder is that it enables good adhesion of the solid lubricants to the substrate surface to be lubricated.
[0067] The binder (b) can be an organic binder and / or an inorganic binder. Organic binders are preferred. If an inorganic binder is used, three-dimensionally cross-linked inorganic materials are preferred.
[0068] Particularly preferred inorganic binders are water glass, phosphates and / or titanates.
[0069] Preferred binders (b) are selected from the group consisting of organic polymers, preferably polyimide (PI), in particular polyamide-imide (PAI), polyurethane (PU), epoxy resin, phenolic resin, phenoxy resin, melamine resin, acrylate resin, polyetheretherketone (PEEK), polyetherketone (PEK), polyethersulfone (PES), polyisocyanate, polyol, silicone resin, and mixtures thereof. Particularly preferred binders (b) are selected from the group consisting of polyamide-imide (PAI), polyurethane (PU), melamine resin, polyisocyanate, and mixtures thereof. Polyurethane (PU) is especially preferred.
[0070] In another embodiment, the binder is at least an organic binder that has been cross-linked with at least one cross-linking agent.
[0071] In a further preferred embodiment, the binder is at least one organic binder selected from polyimide (PI), preferably polyamide-imide (PAI), polyurethane (PU), epoxy resin, phenolic resin, phenoxy resin, melamine resin, acrylate resin, polyisocyanate, polyol, silicone resin and mixtures thereof, which has been crosslinked with at least one crosslinking agent, wherein the crosslinking agent is preferably selected from the group consisting of organic epoxides (EP), in particular bis-epoxides, organic isocyanates and their dimers and trimers, blocked organic isocyanates and their dimers and trimers and carbodiimides, in particular N,N'-dicyclohexylcarbodiimide and mixtures thereof.
[0072] In a preferred embodiment of the invention, the polyisocyanate is a blocked organic isocyanate. Preferred blocked organic isocyanates are blocked with phenol, alcohol, oxime, lactam, amide, pyrazole, triazole, and / or urea groups. According to the invention, the lubricant contains the binder b) in an amount of 5 to 60 wt.%, preferably 10 to 50 wt.%, and particularly 12 to 35 wt.%, in each case based on the total weight of the lubricant. When determining the amount of binder b), any solvents that may be present originating from the raw materials are not taken into account. Instead, the solvents are quantitatively attributed to component c). Therefore, the dry mass of binder b) is relevant for determining its quantity. Similarly, any solvents that may be present originating from other raw materials are quantitatively attributed to component c) and not to the raw materials.
[0073] solvent c)
[0074] According to the invention, the sliding lacquer contains at least one solvent (c). Solvents are liquids at 23°C and 1.013 bar that can at least partially dissolve at least one other component of the sliding lacquer (solid or liquid at 23°C and 1.013 bar). Preferably, no chemical reaction occurs between the solvent and the at least partially dissolved substance.
[0075] Solvents can also have a dispersing effect. Thus, a liquid in a lubricant coating can simultaneously function as both a solvent and a dispersing agent.
[0076] Lubricating lacquers typically contain both substances that are at least partially dissolved by a solvent, and substances that are not dissolved but dispersed by this solvent. For these latter substances, the solvent then acts as a dispersing agent.
[0077] Preferably, the solvent has a boiling point of 23°C and 1.013 bar from 30°C to 300°C, preferably from 20°C to 250°C.
[0078] A solvent-based lubricant is also commonly referred to as a wet lacquer. Preferred solvents are selected from the group consisting of water, aromatic solvents, preferably xylene, ethyl and / or butyl acetates; alcohols, preferably ethanol, butanol and / or glycol, in particular butyldiglycol; ethers; esters, preferably lactones, in particular butyrolactone, butyl acetate and / or ethyl acetate; ketones, preferably methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK); pyrrolidone, preferably methyl 2-pyrrolidone (NMP), N-ethyl 2-pyrrolidone (NEP), N-butyl 2-pyrrolidone (NBP); ketones, morpholine, preferably N-acetyl or N-formylmorpholidone (NFM). Amide, preferably dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and / or 3-methoxy-N,N-dimethylpropanamide (CAS 53185-52-7).
[0079] Particularly preferred solvents are selected from the group consisting of water, aromatic solvent, preferably xylene, ethyl and / or butyl acetates; alcohol, preferably ethanol, butanol and / or glycol, in particular butyldiglycol; ketone, preferably methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK); pyrrolidone, preferably methyl 2-pyrrolidone (NMP), N-ethyl 2-pyrrolidone (NEP), N-butyl 2-pyrrolidone (NBP); morpholine, preferably N-acetyl or N-formylmorpholidone (NFM); amide, preferably dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and / or 3-methoxy-N,N-dimethylpropanamide (CAS 53185-52-7).
[0080] Particularly preferred solvents are selected from the group consisting of water and / or glycol, especially butyldiglycol.
[0081] The amount of solvent c) based on the total weight of the sliding varnish is from 50 wt.% to 80 wt.%, preferably from 60 wt.% to 80 wt.%, even more preferably from 65 wt.% to 80 wt.%.
[0082] Further components d) of the sliding lacquer
[0083] The lubricant may also contain other components, for example, additional solid lubricants, pigments, defoamers, fillers, rheology additives, and / or dispersing additives. Pigments are color-imparting, solid substances that are insoluble in the lubricant. Carbon black is a preferred pigment. The other solid lubricants differ from components a1), a2), a3), and a4). Rheology additives are additives that positively influence the flow and settling behavior of the lubricant. The lubricant may also contain fillers, for example, carbonates and / or mica. If a component used in the lubricant according to the invention has multiple effects, e.g., as a rheology additive and a dispersing additive, it is only considered once in terms of quantity.
[0084] In a preferred embodiment of the invention, the sliding coating contains the further components d), in particular further solid lubricants, pigments, defoamers, fillers, rheology additives and / or dispersing additives in an amount of 1 wt.% to 15 wt.%, preferably 3 wt.% to 10 wt.%, particularly 5 wt.% to 7 wt.%, based on the total weight of the sliding coating. The dry mass of the further components d) is used to determine their quantity. Further preferred embodiments of the sliding coating
[0085] In a preferred embodiment of the invention, the sliding lacquer contains no polytetrafluoroethylene and / or polytetrafluoroethylene in an amount of less than 4 wt.%, preferably less than 1 wt.%, in particular less than 0.1 wt.%, based on the total weight of the sliding lacquer.
[0086] The polytetrafluoroethylene (PTFE) content in the lubricant coating is preferably determined based on the enthalpy of fusion of PTFE according to DIN EN ISO 11357-1, edition 2008.04. The measurement is conveniently carried out as follows: First, the solvent is removed. Then, 20 mg of the residue is weighed into a 25 pl aluminum DSC crucible and heated to 600°C at a heating rate of 10 K / min. The endothermic signal between 300 and 450°C is integrated; the area of the peak (enthalpy sample) is proportional to the amount of PTFE in the residue. For calibration, a pure PTFE micropowder (particle size D50 value according to ASTM D4894-19 = 5 pm, melt flow index at 372°C / 2.16 kg / 2095 mm according to ASTM D1238-23a) = 0.5 g / 10 min) is measured analogously (enthalpy reference). The PTFE content in the lubricant is calculated using the following equation:
[0087] (Enthalpy of sample) / (Enthalpy of reference) * Residue percentage in wt.% = PTFE content in wt.%
[0088] In a further preferred embodiment of the invention, the amount of pigment volume in the lubricant is such that the pigment volume concentration (PVC) of a lubricant layer produced from the lubricant, determined according to PVC = V(P) + V(F) + V(a1 + a2 + a3 + a4) / V(P) + V(F) + V(a1 + a2 + a3 + a4) + V(BM) * 100%, where V(P) = volume of pigments, V(F) = volume of fillers, V(BM) = dry film volumes of all binders, V(a1 + a2 + a3 + a4) = sum of the volumes of the solid lubricants a1) to a4), is from 15% to 65%, more preferably from 20% to 60%, and even more preferably from 25% to 50%. Practical tests have shown that the wear resistance of the lubricant layer is at least satisfactory at these PVC values.In a preferred embodiment of the invention, the amount of pigment volume in the lubricant is such that the pigment volume concentration (PVC) of a lubricant layer produced from the lubricant is 30% to 50%, in particular 30% to 45%.
[0089] In a preferred embodiment of the invention, the sliding lacquer consists of a1) talc in an amount of 2 wt.% to 15 wt.%, preferably 3 wt.% to 13 wt.%, in particular 4 wt.% to 11 wt.%, based on the total weight of the sliding lacquer,
[0090] a2) Graphite in an amount of 0.5 wt.% to 10 wt.%, preferably 0.5 wt.% to 6 wt.%, more preferably 0.5 wt.% to 4 wt.%, in particular 0.5 wt.% to 2 wt.%, based on the total weight of the sliding varnish,
[0091] a3) Polymethylurea in an amount of 0.5 wt.% to 10 wt.%, preferably 2 wt.% to 9 wt.%, more preferably 3 wt.% to 8 wt.%, in particular 3 wt.% to 7 wt.%, based on the total weight of the sliding varnish,
[0092] a4) Boron nitride in an amount of 0.8 wt.% to 5 wt.%, preferably 0.8 wt.% to 4 wt.%, more preferably 0.8 wt.% to 3 wt.%, in particular 0.8 wt.% to 2 wt.%, based on the total weight of the sliding lacquer, b) at least one binder in an amount of 5 wt.% to 60 wt.%, more preferably 10 wt.% to 50 wt.%, in particular 12 wt.% to 35 wt.%, based on the total weight of the sliding lacquer, and c) at least one solvent in an amount of 50 wt.% to 80 wt.%, preferably 60 wt.% to 80 wt.%, in particular 65 wt.% to 80 wt.%, based on the total weight of the sliding lacquer.
[0093] d) at least one further component selected from further solid lubricants, pigments, defoamers, fillers, rheology additives, dispersing additives and mixtures thereof in an amount of 1 wt.% to 15 wt.%, preferably 3 wt.% to 10 wt.%, in particular 5 wt.% to 7 wt.%, based on the total weight of the sliding coating.
[0094] In another preferred embodiment of the invention, the proportions of the following components in the inventive sliding lacquer are:
[0095] a1) Talc of 3 wt.% to 80 wt.%, preferably of 5 wt.% to 80 wt.%, more preferably of 10 wt.% to 70 wt.%, more preferably of 30 wt.% to 70 wt.%, in particular of 50 wt.% to 60 wt.%, based on the total weight of the solid lubricants a1), a2), a3) and a4) taken together,
[0096] a2) Graphite from 3 wt.% to 80 wt.%, preferably from 3 wt.% to 60 wt.%, more preferably from 3 wt.% to 30 wt.%, more preferably from 3 wt.% to 15 wt.%, in particular from 3 wt.% to 10 wt.%, based on the total weight of the solid lubricants a1), a2), a3) and a4) taken together,
[0097] a3) Polymethylurea from 1.5 wt.% to 70 wt.%, preferably from 5 wt.% to 60 wt.%, more preferably from 15 wt.% to 50 wt.%, more preferably from 25 wt.% to 45 wt.%, in particular from 25 wt.% to 40 wt.%, based on the total weight of the solid lubricants a1), a2), a3) and a4) taken together, and
[0098] a4) Boron nitride from 3 wt.% to 70 wt.%, preferably from 3 wt.% to 40 wt.%, more preferably from 3 wt.% to 25 wt.%, in particular from 3 wt.% to 10 wt.%, based on the total weight of the solid lubricants a1), a2), a3) and a4) taken together,
[0099] In another preferred embodiment of the invention, the sliding lacquer contains
[0100] a) 4 wt.% to 40 wt.%, preferably 4 wt.% to 30 wt.%, even more preferably 5 wt.% to 30 wt.%, in particular 10 wt.% to 20 wt.%, based on the total weight of the sliding varnish, containing at least a solid lubricant mixture
[0101] a1) Talc in an amount of 2 wt.% to 15 wt.%, preferably 3 wt.% to 13 wt.%, in particular 4 wt.% to 11 wt.%, based on the total weight of the sliding varnish,
[0102] a2) Graphite in an amount of 0.5 wt.% to 10 wt.%, preferably 0.5 wt.% to 6 wt.%, more preferably 0.5 wt.% to 4 wt.%, in particular 0.5 wt.% to 2 wt.%, based on the total weight of the sliding varnish,
[0103] a3) Polymethylurea in an amount of 0.5 wt.% to 10 wt.%, preferably 2 wt.% to 9 wt.%, more preferably 3 wt.% to 8 wt.%, in particular 3 wt.% to 7 wt.%, based on the total weight of the sliding varnish,
[0104] a4) Boron nitride in an amount of 0.8 wt.% to 5 wt.%, preferably 0.8 wt.% to 4 wt.%, more preferably 0.8 wt.% to 3 wt.%, in particular 0.8 wt.% to 2 wt.%, based on the total weight of the sliding varnish, as well as
[0105] g. at least one binder in an amount of 5 wt.% to 60 wt.%, more preferably 10 wt.% to 50 wt.%, in particular 12 wt.% to 35 wt.%, in each case based on the total weight of the sliding varnish, h. at least one solvent in an amount of 50 wt.% to 80 wt.%, preferably 60 wt.% to 80 wt.%, more preferably 65 wt.% to 80 wt.%, based on the total weight of the sliding varnish.
[0106] In a particularly preferred embodiment of the invention, the lubricant contains
[0107] a) Containing at least 8.3 wt.% to 20 wt.%, based on the total weight of the sliding varnish, a solid lubricant mixture
[0108] a1) Talc in an amount of 4 wt.% to 11 wt.%, based on the total weight of the sliding varnish,
[0109] a2) Graphite in an amount of 0.5 wt.% to 2 wt.%, based on the total weight of the sliding varnish,
[0110] a3) Polymethylurea in an amount of 3 wt.% to 8 wt.%, based on the total weight of the lubricant,
[0111] a4) Boron nitride in an amount of 0.8 wt.% to 2 wt.%, based on the total weight of the sliding varnish, as well as
[0112] g. at least one binder in an amount of 12 wt.% to 35 wt.%,
[0113] based on the total weight of the sliding lacquer,
[0114] h. at least one solvent in an amount of 65 wt.% to 80 wt.%, based on the total weight of the sliding varnish.
[0115] In a further preferred embodiment of the invention, the quantity of components a1), a2), a3), a4), b) and c) taken together, based on the total weight of the sliding varnish, is at least 64 wt.%, for example from 64 wt.% to 100 wt.%, preferably 75 wt.% to 100 wt.%.
[0116] Powder coatings
[0117] Another object of the invention is a powder coating comprising
[0118] a) containing at least a solid lubricant mixture
[0119] a1) Talc,
[0120] a2) Graphite,
[0121] a3) Polymethylurea,
[0122] a4) Boron nitride,
[0123] b) at least one binder. In a preferred embodiment, the amount of solvent based on the total weight of the powder coating is less than 4 wt.%, preferably less than 1 wt.%.
[0124] Preferred embodiments for the powder coating according to the invention comprise the embodiments described above and below for the sliding coating according to the invention, mutatis mutandis.
[0125] Preferably the powder coating contains
[0126] a1) Talc in an amount of 4 wt.% to 60 wt.%, preferably 6 wt.% to 52 wt.%, in particular 8 wt.% to 44 wt.%, based on the total weight of the powder coating,
[0127] a2) Graphite in an amount of 1 wt.% to 40 wt.%, preferably 1 wt.% to 24 wt.%, more preferably 1 wt.% to 16 wt.%, in particular 1 wt.% to 8 wt.%, based on the total weight of the powder coating, a3) Polymethylurea in an amount of 1 wt.% to 40 wt.%, preferably 4 wt.% to 36 wt.%, more preferably 6 wt.% to 32 wt.%, in particular 6 wt.% to 28 wt.%, based on the total weight of the powder coating,
[0128] a4) Boron nitride in an amount of 1.6 wt.% to 20 wt.%, preferably 1.6 wt.% to 16 wt.%, more preferably 1.6 wt.% to 12 wt.%, in particular 1.6 wt.% to 8 wt.%, based on the total weight of the powder coating,
[0129] b) at least one binder in an amount of 10 wt.% to 92 wt.%, more preferably 20 wt.% to 90 wt.%, in particular 30 wt.% to 90 wt.%, based on the total weight of the powder coating.
[0130] The powder coating can be produced using a solid lubricant mixture containing at least
[0131] a1) Talc,
[0132] a2) Graphite,
[0133] a3) Polymethylurea,
[0134] a4) Boron nitride.
[0135] Sliding lacquer layer: Another object of the invention is a sliding lacquer layer comprising
[0136] f . containing at least a solid lubricant mixture
[0137] a1) Talc,
[0138] a2) Graphite,
[0139] a3) Polymethylurea,
[0140] a4) Boron nitride,
[0141] g. at least one at least partially cured binder.
[0142] In a preferred embodiment, the amount of solvent, based on the total weight of the sliding lacquer layer, is less than 4 wt.%, and even more preferably less than 1 wt.%. In the sliding lacquer layer according to the invention, the binder is at least partially cured. Preferably, the binder is completely cured.
[0143] The sliding lacquer layer according to the invention is preferably produced from the sliding lacquer according to the invention. The production process preferably comprises applying the sliding lacquer to a substrate and at least partially curing the binder b). The curing of the binder b) preferably takes place after the application of the sliding lacquer to the substrate. The curing of the at least one binder b) can be carried out by a physical curing process, for example, by a drying process and / or a chemical curing process. As a rule, the solvent contained in the sliding lacquer evaporates during curing.
[0144] Preferred embodiments for the sliding lacquer layer according to the invention comprise the embodiments described above and below for the sliding lacquer according to the invention, mutatis mutandis.
[0145] Preferably the sliding lacquer layer contains
[0146] a1) Talc in an amount of 4 wt.% to 60 wt.%, preferably 6 wt.% to 52 wt.%, in particular 8 wt.% to 44 wt.%, based on the total weight of the sliding lacquer layer,
[0147] a2) Graphite in an amount of 1 wt.% to 40 wt.%, preferably 1 wt.% to 24 wt.%, more preferably 1 wt.% to 16 wt.%, in particular 1 wt.% to 8 wt.%, based on the total weight of the sliding lacquer layer, a3) Polymethylurea in an amount of 1 wt.% to 40 wt.%, preferably 4 wt.% to 36 wt.%, more preferably 6 wt.% to 32 wt.%, in particular 6 wt.% to 28 wt.%, based on the total weight of the sliding lacquer layer,
[0148] a4) Boron nitride in an amount of 1.6 wt.% to 20 wt.%, preferably 1.6 wt.% to 16 wt.%, more preferably 1.6 wt.% to 12 wt.%, in particular 1.6 wt.% to 8 wt.%, based on the total weight of the sliding lacquer layer,
[0149] b) at least one binder in an amount of 10 wt.% to 92 wt.%, more preferably 20 wt.% to 90 wt.%, in particular 30 wt.% to 90 wt.%, based on the total weight of the powder coating.
[0150] In a preferred embodiment of the invention, the sliding lacquer layer according to the invention contains no polytetrafluoroethylene and / or polytetrafluoroethylene in an amount of less than 8 wt.%, preferably less than 2 wt.%, in particular less than 0.2 wt.%, based on the total weight of the sliding lacquer layer.
[0151] Preferably, the thickness of the sliding lacquer layer is no more than 70 pm, for example, 1 pm to 70 pm, even more preferably from 10 pm to 40 pm. The layer thickness is measured microscopically by preparing a cross-section perpendicular to the sliding lacquer according to DIN EN ISO 2808 (2019). For magnetizable, ferromagnetic substrates, the magnetic induction method is used. For non-magnetizable substrates, the measurement is taken according to method 5.4.4.2, cross-sectional variant.
[0152] In a preferred embodiment of the invention, the pigment volume concentration (PVC) of the sliding coating is determined according to PVC = V(P) + V(F) + V(a1 + a2 + a3 + a4) / V(P) + V(F) + V(a1 + a2 + a3 + a4) + V(BM) * 100%, where V(P) = volume of pigments, V(F) = volume of fillers, V(BM) = dry film volumes of all binders, and V(a1 + a2 + a3 + a4) = sum of the volumes of the solid lubricants a1) to a4), from 15% to 65%, more preferably from 20% to 60%, and even more preferably from 25% to 50%. Practical tests have shown that the wear resistance of the sliding coating is at least satisfactory at these PVC values. In a preferred embodiment of the invention, the pigment volume concentration (PVC) of the sliding lacquer layer is from 30% to 50%, particularly from 30% to 45%. Practical tests have shown that at PVC values below 50%, the solid lubricants and, if applicable, the lubricants are reduced.Existing fillers are particularly well wetted and therefore especially stably bound in the lubricant. At the same time, particularly good wear resistance can be achieved with a pigment volume concentration (PVC) of the lubricant layer of 30% and higher. Applications and processes.
[0153] A further aspect of the present invention comprises the use of a sliding coating, a powder coating, and / or a sliding coating layer according to the invention, as described above and below, for the lubrication of a tribological system, in particular a tribological system in the automotive sector. The use of the sliding coating according to the invention is particularly preferred.
[0154] A tribological system is, in general terms, a technical system that enables, influences, or prevents movement through contact and whose essential components include the pairs of contact surfaces involved in tribological stress and the collective load acting upon them. Typically, a tribological system comprises at least one base body that is in contact and relative motion with at least one counter body. The collective load includes the load applied to the bodies, as well as the motion conditions, the state of friction, and the temperature. An intermediate material is often present between the two bodies; this may specifically be a sliding coating, powder coating, and / or a sliding coating layer applied to reduce wear.
[0155] The inventive sliding coating, powder coating, and / or sliding coating layer are preferably used for lubricating a base body of a tribological system, particularly a tribological system in the automotive sector. Preferred base bodies comprise elastomers and / or metallic materials. The base body can contain both metallic and non-metallic materials, preferably composite materials, aluminum, aluminum alloys, steel, stainless steel, and cast materials, non-ferrous metals, plastics, fiber-reinforced plastics, and / or polymers, in particular TPV (thermoplastic vulcanizates). In a preferred embodiment, the tribological system comprises a base body that contains polymers, in particular elastomers and / or TPV (thermoplastic vulcanizates), as its base material.
[0156] In a particularly preferred embodiment, the base body comprises polymers, in particular elastomers and / or TPV (thermoplastic vulcanizates), as a base material. Further, and particularly preferably, the base body comprises polymers, in particular elastomers and / or TPV (thermoplastic vulcanizates), as a base material, which incorporate flock fibers. The term "as a base material" means that the base body comprises more than 50% by weight of the respective material. Thermoplastic vulcanizates (TPVs) are thermoplastic elastomers (TPEs) that undergo a vulcanization process during their manufacture. This process leads to the cross-linking of the polymer chains, which increases the strength, durability, and flexibility of the final product. Flock fibers (also called flocking) are staple fibers (fiber length 0.1 to 1 mm, preferably 0.2 to 0.8 mm) applied to a surface to give it a velvety, soft, or textured surface.Preferably, the flock fibers contain plastics such as nylon, rayon, or polyester. The flock fibers are preferably applied to the substrate by an electrostatic process. The process preferably comprises the following steps:
[0157] - Applying an adhesive: First, an adhesive and / or a bonding layer is applied to the base material.
[0158] - Applying the flock fibers: The flock fibers are electrostatically charged.
[0159] This allows them to align themselves perpendicular to the adhesive layer and adhere to it. This method ensures that the fibers are applied evenly and vertically to the surface, resulting in a uniform and dense texture.
[0160] Drying: After the fibers are applied, the adhesive is dried or hardened to permanently fix the flock fibers.
[0161] In a particularly preferred embodiment, the base body comprises polymers, in particular elastomers and / or TPV (thermoplastic vulcanizates), as the base material, which have flock fibers, wherein the flock fibers are applied to the base body by an electrostatic process comprising the following steps:
[0162] An adhesive and / or a bonding layer is applied to the base body; electrostatically charged flock fibers are applied to the base body coated with adhesive and / or a bonding layer.
[0163] The adhesive is dried and / or hardened to fix the flock fibers.
[0164] Flocking is versatile and offers both aesthetic advantages and functional properties such as non-slip surfaces, improved haptics and sound absorption.
[0165] In a preferred embodiment, the inventive sliding lacquer, the inventive powder coating and / or the inventive sliding lacquer layer is used for lubricating a base body of a tribological system, in particular a tribological system in the automotive sector, wherein the base body is selected from door seals, preferably base profiles of door seals, in particular stained base profiles of door seals, air conditioning compression pistons, bearing shells, sliding bearing shells, sealing rings and / or profile seals.
[0166] In a further preferred embodiment, the counterbody in the tribological system comprises composite materials, aluminum, aluminum alloys, steel, stainless steel and cast materials, non-ferrous metals, plastics, fiber-reinforced plastics, polymers, glass and / or clear-coated metal and / or mixtures thereof. Particularly preferred polymers are polyoxymethylene (POM) and / or polyamides. Furthermore, it is conceivable that the counterbody is also coated with a sliding lacquer and / or clear lacquer. Preferably, the counterbody comprises plastics, polymers, glass and / or clear-coated metal and / or mixtures thereof. Glass and / or clear-coated metal is particularly preferred. The selection of these materials allows for weight savings and cost reduction.
[0167] In a particularly preferred embodiment of the invention, the inventive sliding varnish, the inventive powder coating and / or the inventive sliding varnish layer is used for lubricating a base body of a tribological system, wherein the base body comprises polymers, in particular elastomers and / or TPV (thermoplastic vulcanizates), which have flock fibers. As explained above, the use of the sliding varnish is particularly preferred in this application.
[0168] In a particularly preferred embodiment of the invention, the base body comprises polymers as a material, preferably elastomers and / or TPV (thermoplastic vulcanizates), in particular elastomers and / or TPV (thermoplastic vulcanizates) having flock fibers, and the counter body comprises glass and / or metal coated with clear lacquer. These combinations have proven particularly advantageous, especially for components in the automotive sector, as they represent a particularly good combination of properties with regard to cost, functionality, and weight.
[0169] Another aspect of the present invention comprises a method for lubricating tribological systems comprising the following steps:
[0170] 1) a sliding lacquer comprising a1) talc in an amount of 2 wt.% to 15 wt.%, preferably 3 wt.% to 13 wt.%, in particular 4 wt.% to 11 wt.%, based on the total weight of the sliding lacquer,
[0171] a2) Graphite in an amount of 0.5 wt.% to 10 wt.%, preferably 0.5 wt.% to 6 wt.%, more preferably 0.5 wt.% to 4 wt.%, in particular 0.5 wt.% to 2 wt.%, based on the total weight of the sliding varnish,
[0172] a3) Polymethylurea in an amount of 0.5 wt.% to 10 wt.%, preferably 2 wt.% to 9 wt.%, more preferably 3 wt.% to 8 wt.%, in particular 3 wt.% to 7 wt.%, based on the total weight of the sliding varnish,
[0173] a4) Boron nitride in an amount of 0.8 wt.% to 5 wt.%, preferably 0.8 wt.% to 4 wt.%, more preferably 0.8 wt.% to 3 wt.%, in particular 0.8 wt.% to 2 wt.%, based on the total weight of the sliding lacquer, b) at least one binder in an amount of 5 wt.% to 60 wt.%, more preferably 10 wt.% to 50 wt.%, in particular 12 wt.% to 35 wt.%, based on the total weight of the sliding lacquer, and
[0174] c) at least one solvent in an amount of 50 wt.% to 80 wt.%, preferably 60 wt.% to 80 wt.%, in particular 65 wt.% to 80 wt.%, based on the total weight of the sliding varnish,
[0175] is applied to at least one surface of a base body of a tribological system;
[0176] 2) the at least one binder b) is at least partially hardened.
[0177] For the method according to the invention, a sliding lacquer according to one or more of the preceding and following embodiments is preferably used. The application of the sliding lacquer to the at least one surface of the base body can be carried out by known methods, for example by spraying, dipping, centrifuging, drumming and / or printing. Preferred application methods are selected from spraying processes, including electrostatically assisted spraying, doctor blade application, dispensing, brushing, dipping, immersion centrifuging, drumming, rolling, and printing processes such as screen printing or printing.
[0178] Pad printing. The curing of the at least one binder b) can be carried out by a physical curing process, in particular by a drying process and / or a chemical curing process.
[0179] Preferred embodiments of the use and / or method according to the invention include embodiments of the inventive sliding lacquer described above or below, mutatis mutandis.
[0180] Tribological system
[0181] A further object of the invention is a tribological system comprising at least one base body which is in contact and relative motion with at least one counter body, wherein the base body and optionally also the counter body contains on at least one surface a sliding coating according to the invention, a powder coating according to the invention and / or a sliding coating layer according to the invention.
[0182] Preferred base bodies and counter bodies are those described above and below for the methods and uses according to the invention.
[0183] The base body can be subjected to common pretreatments such as sandblasting, phosphating, smoothing, roughening, for example to improve the adhesion of the sliding coating and the corrosion resistance of the coated base body.
[0184] The invention will be explained in more detail below using several non-limiting examples.
[0185] 1. Materials used
[0186] Basecoat A
[0187]
[0188]
[0189]
[0190] When determining the proportions of the components of the sliding coating, solvents derived from the raw materials are quantitatively allocated to component c) (solvents). Therefore, the dry mass of the components of the sliding coating, with the exception of component c), is relevant for determining their respective quantities.
[0191] Basecoat A is produced by sequentially mixing the components. After adding deionized water, the rheology additives and a surfactant are added while stirring with a toothed disc. In the subsequent manufacturing process, further surfactants, preservatives, UV indicator and UV protectant, as well as binders, are added and sheared using a rotor-stator system. Finally, the pH is adjusted with base while stirring.
[0192] Starting from basecoat A, comparison coatings and coatings according to the invention are produced by mixing in the respective solid lubricants and shears using a rotor-stator system.
[0193] Inventive sliding coating 1:
[0194]
[0195]
[0196] The inventive sliding coating 1 is produced by successive mixing of the components (with the exception of the solid lubricants). After adding demineralized water, the rheology additives and a surfactant are added while stirring with a toothed disc. The solid lubricants are then added and subsequently sheared using a rotor-stator system. In the further production process, additional surfactants, preservatives, a UV indicator and UV protectant, as well as binders, are added and sheared using a rotor-stator system. Finally, the pH is adjusted with a base while stirring. The fine distribution of the solid lubricants is ensured by a grindometer test. If any coarse particles remain, the mixture is sheared again using the rotor-stator system.
[0197] Analogous to this procedure, the comparison lacquers shown in the following table and the sliding lacquers 2a, 2b, 3a and 4a according to the invention are produced.
[0198]
[0199]
[0200] The amount of solid lubricant [wt.%] is based on the total weight of the sliding coating (base coat + solid lubricants).
[0201] The composition of the sliding coatings 2a, 2b, 3a and 4a according to the invention is shown in tabular form below:
[0202] Inventive paint 2a (PVK 33.3)
[0203]
[0204]
[0205] Inventive lacquer 2b (PVK = 42.7)
[0206]
[0207]
[0208] Inventive sliding coating 3a:
[0209]
[0210]
[0211] The inventive sliding varnish 3a is produced by successive mixing of the components (with the exception of the solid lubricants). After adding demineralized water, the rheology additives and a surfactant are added while stirring with a toothed disc. The solid lubricants are then added and subsequently sheared using a rotor-stator system. In the further production process, additional surfactants, preservatives, a UV indicator and UV protectant, as well as binders, are added and sheared using a rotor-stator system. Finally, the pH is adjusted with a base while stirring. The fine distribution of the solid lubricants is ensured by a grindometer test. If any coarse particles remain, the mixture is sheared again using the rotor-stator system.
[0212] Inventive sliding coating 4a:
[0213]
[0214]
[0215] The sliding lacquer 4a according to the invention is produced analogously to sliding lacquer 3a.
[0216] The sliding coatings according to the invention and the comparison coatings are produced as follows: The coatings are applied to cleaned and plasma-activated elastomer bodies (EPDM) using a spray gun (variant A). Flock materials are also used, which are not pretreated (variant B). After a short flash-off period (room temperature), drying takes place at 105°C for 10-20 minutes. The resulting sliding coatings have a thickness of approximately 10 µm.
[0217] 2. Testing according to Zins Ziegler using the SSP-04 (stick-slip test bench)
[0218] The sliding lacquer coatings from Example 1 (Variant A) are tested according to Zins Ziegler (VDA 230-206 Part I of 2005). The following parameters are used:
[0219]
[0220]
[0221] 2.1 The test at room temperature yields the following results:
[0222]
[0223] It is shown that the sliding coatings according to the invention exhibit very low RPNs, which are even lower than those of PTFE. Furthermore, the sliding coatings according to the invention exhibit excellent coefficients of friction, which are even lower than those of PTFE. The coefficients of friction are averaged over all periods.
[0224] 2.2 The test at 80°C yields the following results:
[0225]
[0226] It is shown that the sliding coatings according to the invention exhibit very low RPNs, comparable to those of PTFE. Furthermore, the sliding coatings according to the invention exhibit excellent coefficients of friction, some of which are even lower than those of PTFE. The coefficients of friction are averaged over all periods.
[0227] 3. Zwicki Friction Coefficient Test: The friction coefficients are determined using the Zwicki friction coefficient test. The following test conditions are used:
[0228]
[0229]
[0230]
[0231] It is shown that the sliding coatings according to the invention exhibit very low coefficients of friction, equivalent to BN and even lower than those of PTFE in all cases. This is remarkable, as BN is an excellent solid lubricant. However, a disadvantage of BN is that it is extremely expensive and difficult to stabilize in formulations at higher concentrations. This can lead to inhomogeneities in the coating layer and short formulation shelf lives.
[0232] 4. Wear test
[0233] Wear tests are performed using a crockmeter. The tests are carried out as follows:
[0234] 1. Preparation: Elastomeric bodies in the form of elastomer strips are coated with the sliding lacquers to be tested, cured, and placed dry on the test bench. The resulting sliding lacquer layers have a thickness of approximately 10 µm.
[0235] 2. Test Procedure: The test rig then performs oscillating movements (max. 10,000 cycles or until the sliding lacquer coating is worn out), which serve to move the coated elastomer strip against a friction partner (textile stamp / glass chisel). These movements are performed at a speed of 10 cm / s and under a contact force of 5 N or 10 N.
[0236] 3. Evaluation of the results: After the test (duplicate determination), the sliding lacquer layer is visually inspected for changes (wear / abrasion). The number of cycles until complete wear is determined.
[0237] The results are shown in the following table.
[0238] > > >
[0239]
[0240] > >
[0241] > >
[0242] >
[0243] >
[0244] >
[0245] >
[0246]
[0247] It has been shown that the inventive sliding coatings come very close to the performance of PTFE. Surprisingly, the inventive sliding coating 1 exhibited significantly improved abrasion resistance values in the glass test compared to sliding coatings containing only individual solid lubricants. The acrylate binder-based sliding coating 4a achieves significantly better wear resistance against glass compared to the reference coating B, which contains PTFE. The comparatively low abrasion resistance of graphite can also be significantly improved by incorporating it into the solid lubricant mixture.
[0248] 5. Production and testing of further sliding lacquer layers according to the invention. The sliding lacquers 3 to 20 according to the invention are produced starting from base lacquer A by different amounts of the solid lubricants, resulting in different PVK values of the sliding lacquer layers produced from them, as shown in the following table.
[0249] These sliding lacquers (GL) are used to produce sliding lacquer coatings and wear tests are carried out using a crockmeter.
[0250] The results are shown in the following table.
[0251]
[0252]
[0253] The sliding coatings listed in the table are sliding coatings according to the invention.
[0254] The following densities are used to determine the PVK.
[0255]
[0256] It appears that the wear resistance of the investigated sliding coatings is at least satisfactory.
[0257] The sliding lacquer layers obtained from the inventive sliding lacquers 3 to 20 and comparison lacquer A are tested according to Zins Ziegler (VDA 230-206 Part I of 2005). The results are shown in the following table. EPDM,
[0258] room temperature
[0259]
[0260]
[0261] It turns out that the friction coefficient and stick-slip behavior of the investigated sliding coatings is at least satisfactory.
[0262] The sliding lacquer layers obtained from the inventive sliding lacquers 3 to 20 and the reference lacquer A are tested using a crockmeter. The results are shown in the following table.
[0263]
[0264]
[0265] It turns out that the abrasion resistance of the investigated sliding coatings is at least satisfactory.
[0266] 6. Testing of selected sliding lacquer coatings
[0267] Selected sliding lacquer coatings are tested using Zins-Ziegler.
[0268] Flock, RT and 80°C
[0269] (Variant B)
[0270]
[0271]
[0272]
[0273] It turns out that the investigated sliding coatings almost reach the performance of the comparison coating A, or in some cases even exceed it.
[0274] Measurement methods
[0275] Room temperature: The room temperature (RT) is 23°C.
[0276] Particle size
[0277] Unless otherwise expressly stated, particle size is determined in accordance with ISO 13320, 2020-01-01. The particle size used here refers to the diameter of the particle. In general, a compound or sample contains a multitude of particles of different sizes, so the particle size of the compound or sample is a distribution. Unless otherwise expressly stated, the particle size used here refers to the maximum size that the specified volume percent, e.g., 90 or 50 volume percent, of the particles in the compound or sample have; that is, the size corresponds to the largest size, e.g., of 90 or 50 volume percent of the smallest particles (often denoted as x90; see method ISO 13320-1:1999 for further details). Instruments and methods for determining the particle size of pesticides are known to a person competent in this field. Examples of suitable instruments are Malvern Mastersizer S, CILAS, COULTER COUNTER, and Heios (SYMPATEC). Measurement is performed on dry surfaces.The Fraunhofer theory is used for the evaluation.
[0278] Pigment Volume Concentration (PVC)
[0279] The pigment volume concentration (PVC) is the ratio of pigment volume to the total volume of the (dried) coating film [vol. %); pigment volume is understood to be the sum of pigment and filler volumes. The PVC is described in "Lackformulierung und Lackrezeptur" by Bodo Müller / Ulrich Poth, published as 2.
[0280] Edition, 2005, published by Vincentz Verlag. A slightly modified formula is used for the present invention:
[0281] PVK = V (P) + V (F) + V (a1 + a2 + a3 + a4) / V (P) + V (F) + V (a1 + a2 + a3 + a4) + V (BM) * 100%,
[0282] where
[0283] V (P) = Volume of pigments,
[0284] V (F) = Volume of fillers,
[0285] V (BM) = Dry film volumes of all binders,
[0286] V (a1 + a2 + a3 + a4) = Sum of the volumes of the solid lubricants a1) to a4)
[0287] If other solid lubricants are present, they are added to the quantity of solid lubricants a1) to a4).
[0288] dry matter
[0289] The dry matter content is determined according to DIN EN ISO 3251:2019 Paints, varnishes and plastics - Determination of non-volatile-matter content (ISO 3251:2019). Proportion of extractable components
[0290] The determination of the proportion of extractable components is carried out according to ISO 6427:2014-08. The test conditions for copolyamide are selected.
Claims
Patent claims 1. Sliding lacquer comprehensive a1) Talc in an amount of 2 wt.% to 15 wt.%, based on the total weight of the sliding varnish, a2) Graphite in an amount of 0.5 wt.% to 10 wt.%, based on the total weight of the sliding varnish, a3) Polymethylurea in an amount of 0.5 wt.% to 10 wt.%, based on the total weight of the sliding varnish, a4) Boron nitride in an amount of 0.8 wt.% to 5 wt.%, based on the total weight of the lubricant, b) at least one binder in an amount of 5 wt.% to 60 wt.%, based on the total weight of the sliding varnish, as well as c) at least one solvent in an amount of 50 wt.% to 80 wt.%, based on the total weight of the sliding varnish.
2. Lubricating lacquer according to claim 1, characterized in that the amount of talc a1), based on the total weight of the lubricating lacquer, is from 3 wt.% to 13 wt.%, in particular from 4 wt.% to 11 wt.%.
3. Lubricating varnish according to claim 1 or 2, characterized in that the talc a1) has a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 from 1 pm to 20 pm, preferably from 1 pm to 10 pm, in particular from 2 pm to 6 pm, and / or has a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 from 1 pm to 20 pm, preferably from 5 pm to 15 pm, in particular from 5 pm to 10 pm.
4. Sliding lacquer according to one or more of the preceding claims, characterized in that the amount of graphite a2), based on the total weight of the sliding lacquer, is from 0.5 wt.% to 6 wt.%, more preferably from 0.5 wt.% to 4 wt.%, in particular from 0.5 wt.% to 2 wt.%.
5. Sliding lacquer according to one or more of the preceding claims, characterized in that the graphite a2) has a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 1 pm to 10 pm, in particular of 2 pm to 6 pm and / or that the graphite has a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 of 1 pm to 20 pm, preferably of 5 pm to 15 pm, in particular of 5 pm to 10 pm.
6. Sliding lacquer according to one or more of the preceding claims, characterized in that the amount of polymethylurea a3), based on the total weight of the sliding lacquer, is from 2 wt.% to 9 wt.%, more preferably from 3 wt.% to 8 wt.%, in particular from 3 wt.% to 7 wt.%.
7. Lubricating varnish according to one or more of the preceding claims, characterized in that the polymethylurea a3) has a particle size distribution characterized by a D50 value according to ISO 13320, 2020-01-01 from 1 pm to 20 pm, preferably from 1 pm to 10 pm, more preferably from 2 pm to 7 pm, in particular from 2 pm to 6 pm, and / or the polymethylurea has a particle size distribution characterized by a D90 value according to ISO 13320, 2020-01-01 from 1 pm to 20 pm, preferably from 5 pm to 15 pm, more preferably from 5 pm to 13 pm, in particular from 5 pm to 10 pm.
8. Lubricating varnish according to one or more of the preceding claims, characterized in that the polymethylurea a3) has an OH content of less than 0.3 wt.%, for example of 0.01 wt.% to 0.3 wt.%, based on the total weight of the polymethylurea.
9. Sliding lacquer according to one or more of the preceding claims, characterized in that the amount of boron nitride, based on the total weight of the sliding lacquer, is from 0.8 wt.% to 4 wt.%, more preferably from 0.8 wt.% to 3 wt.%, in particular from 0.8 wt.% to 2 wt.%.
10. Sliding lacquer according to one or more of the preceding claims, characterized in that the sliding lacquer contains a solid lubricant mixture comprising talc, graphite, polymethyl urea and boron nitride, wherein the amount of the solid lubricant mixture is from 4 wt.% to 40 wt.%, more preferably from 4 wt.% to 30 wt.%, more preferably from 5 wt.% to 30 wt.%, in particular from 10 wt.% to 20 wt.%, based on the total weight of the sliding lacquer.
11. Sliding lacquer according to one or more of the preceding claims, characterized in that the sliding lacquer does not contain polytetrafluoroethylene and / or polytetrafluoroethylene in an amount of less than 4 wt.%, based on the total weight of the sliding lacquer.
12. Lubricating lacquer according to one or more of the preceding claims, characterized in that the binder b) is selected from the group consisting of polyimide (PI), in particular polyamide-imide (PAI), polyurethane (PU), epoxy resin, phenolic resin, phenoxy resin, melamine resin, acrylate resin, polyetheretherketone (PEEK), polyetherketone (PEK), polyethersulfone (PES), polyisocyanate, polyol, silicone resin and mixtures thereof.
13. Lubricating lacquer according to one or more of the preceding claims, characterized in that the solvent c) is selected from the group consisting of water, aromatic solvent, preferably xylene, ethyl and / or butyl acetates; alcohol, preferably ethanol, butanol and / or glycol, in particular butyldiglycol; ether; ester, preferably lactone, in particular butyrolactone, butyl acetate and / or ethyl acetate; ketone, preferably methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK); pyrrolidone, preferably methyl 2-pyrrolidone (NMP), N-ethyl 2-pyrrolidone (NEP), N-butyl 2-pyrrolidone (NBP); ketone, morpholine, preferably N-acetyl or N-formylmorpholidone (NFM); Amide, preferably dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and / or 3-methoxy-N,N-dimethylpropanamide (CAS 53185-52-7).
14. Powder coating including a1) Talc in an amount of 4 wt.% to 60 wt.%, based on the total weight of the powder coating, a2) Graphite in an amount of 1 wt.% to 40 wt.%, based on the total weight of the powder coating, a3) Polymethylurea in an amount of 1 wt.% to 40 wt.%, based on the total weight of the powder coating, a4) Boron nitride in an amount of 1.6 wt.% to 20 wt.%, based on the total weight of the powder coating, g. at least one binder in an amount of 10 wt.% to 92 wt.%, based on the total weight of the powder coating.
15. Sliding lacquer layer made from a sliding lacquer according to one or more of claims 1 to 13 comprising a1) talc in an amount of 4 wt.% to 60 wt.%, based on the total weight of the sliding lacquer layer, a2) Graphite in an amount of 1 wt.% to 40 wt.%, based on the total weight of the sliding lacquer layer, a3) Polymethylurea in an amount of 1 wt.% to 40 wt.%, based on the total weight of the sliding lacquer layer, a4) Boron nitride in an amount of 1.6 wt.% to 20 wt.%, based on the total weight of the sliding lacquer layer, b) at least one binder in an amount of 10 wt.% to 92 wt.%, based on the total weight of the sliding lacquer layer.
16. Sliding lacquer coating according to claim 15, characterized in that the pigment volume concentration (PVC) of the sliding lacquer coating is determined according to PVC = V (P) + V (F) + V (a1 + a2 + a3 + a4) / V (P) + V (F) + V (a1 + a2 + a3 + a4) + V (BM) * 100%, where V (P) = volume of pigments, V (F) = volume of fillers, V (BM) = dry film volumes of all binders, V (a1 + a2 + a3 + a4) = sum of the volumes of the solid lubricants a1) to a4), and is from 15% to 65%.
17. Use of a sliding coating according to one or more of claims 1 to 13, a powder coating according to claim 14 and / or a sliding coating according to claim 15 or 16, in particular a sliding coating according to one or more of claims 1 to 13, for lubricating a tribological system, in particular a tribological system in the automotive sector.
18. Use according to claim 17, characterized in that the sliding lacquer, the powder coating and / or the sliding lacquer layer is used for lubricating a base body of a tribological system, wherein the base body is selected from door seals, preferably base profiles of door seals, in particular stained base profiles of door seals, air conditioning compression pistons, bearing shells, sliding bearing shells, sealing rings and / or profile seals.
19. Use according to claim 17 or 18, characterized in that the sliding lacquer, the powder coating and / or the sliding lacquer layer is used for lubricating a base body of a tribological system, wherein the base body contains polymers having flock fibers as a base material.