Coated wiping blade

Abstract

TITLE: Coated Wiper Blade. Wiper blade for a windshield wiper arm comprising a blade body (20) having a coating (26) of particles (22a, 22b), particularly to reduce friction, wiper blade characterized in that: - the coating (26) comprises first particles (22a) having a first average particle diameter and second particles (22b) having a second particle diameter, - the ratio between the first and second average particle diameters is > 2.5 and in particular > 3.5. Figure 4

Description

Title of the invention: Coated wiping blade FIELD OF THE INVENTION

[0001] The present invention relates to a wiping blade for a wiper blade of a windshield wiper comprising a blade base body having a particle coating in particular for reducing friction. STATE OF THE ART

[0002] To reduce friction, wiper blades or wiper blade profiles are usually provided with a friction-reducing agent. This allows for a good wiping image while avoiding noise. In addition, it prolongs the service life of such a wiper blade profile.

[0003] The important components of such a coating are on the one hand the friction-reducing particles, for example in the form of graphite, and on the other hand a suitable binder for attaching such particles to the surface of a wiper blade profile and also for connecting the particles to each other. Usually, very low binder contents are provided in such coatings to prevent the sliding friction coefficient of the coating from being influenced by the binder.

[0004] Wiper blades of this type are, for example, those described in document JP 2000160018 A WO 2019 / 002335 AL

[0005] DISCLOSURE AND ADVANTAGE OF THE INVENTION

[0006] The present invention aims to overcome these drawbacks and has as its subject a wiping blade for a wiper blade of a windscreen wiper comprising a blade base body having a coating of particles in particular to reduce friction,

[0007] wiping blade characterized in that

[0008] - the coating comprises first particles having a first average diameter particle and second particles having a second particle diameter,

[0009] - the ratio between the first and second average particle diameter is > 2.5 and notably > 3.5.

[0010] In other words, the wiper blade is provided with a coating with friction-reducing particles by the combination of first particles having a first average particle diameter and second particles having a second average particle diameter, the first and second particles being significantly different in size such that the ratio of the first to the second average particle diameter is greater than 2.5 and especially greater than 3.5. The particular advantage of this feature is the combination of the respective advantages of the particles of a relatively large diameter to the advantages of particles having a relatively small diameter.

[0011] While the relatively large diameter particles make it possible to have coatings with a very low sliding friction coefficient and a high quality surface, they have the disadvantage of requiring a relatively high binder content to ensure that the particles are guaranteed to be fixed to the surface of the wiper blade, which can result in an increase in the sliding friction coefficient. The addition of the second particles of relatively small diameter makes it possible to have a much higher binder content without increasing the sliding friction coefficient of the coating. In this way, good sliding friction properties and good reliability of this surface coating are achieved at the same time.

[0012] According to an advantageous characteristic, the first and second particles are in different materials, which allows a sliding friction profile of the corresponding coating of the wiper blade that is more targeted than for particles of the same composition but of different particle sizes. For example, a combination of graphite particles and polytetrafluoroethylene particles results in less sliding friction than a coating that contains only graphite particles.

[0013] According to another advantageous characteristic, the particles used are made of graphite, graphene, polytetrafluoroethylene, polyethylene, polypropylene, molybdenum disulfide and / or tungsten disulfide. Particularly preferably, the particles are made of graphite, polytetrafluoroethylene and polyethylene.

[0014] The advantage of using these materials is to have a lower sliding friction coefficient of the surface coating of the wiper blade.

[0015] Furthermore, it is advantageous for the first particles to have a first diameter of between 3 and 20 μm and for the second particles to have an average particle diameter of between 0.1 and 4 μm. The use of such particles makes it possible to have wiper blade coatings having an optimal coating thickness, while at the same time having a relatively high ratio between the first and second particle diameters.

[0016] According to another advantageous characteristic, at least the second particles are made of a fluorinated or fluorine-containing material, such as polytetrafluoroethylene or polyvinyl fluoride.

[0017] According to another advantageous development, the coating contains a binder, for example, polyacrylate, polyurethane, polystyrene, epoxy, polyester, polyether or mixtures thereof; in particular preferably, it is polyacrylate, polyurethane or polystyrene.

[0018] In order to have an abrasion-resistant coating of the wiper blade, it is particularly advantageous for this coating of the wiper blade to contain a binder which further comprises a crosslinking agent. The binder is, for example, a single-component system and the crosslinking agent is a relatively slow-reacting agent or a crosslinking agent which is initially blocking and which is premixed with other components to activate it in the treatment.

[0019] Another possibility is to process the binder as a two-component system and add the crosslinking agent to the binder matrix.

[0020] The crosslinking agents which can be used are, for example: carbodiimide, organosiloxane, melamine, amide, phenolene, isocyanate or their mixtures, in particular in the form of a copolymer or a block copolymer.

[0021] The wiping blade itself is advantageously, for example, based on ethylene-propylene-diene rubber (EPDM), ethylene propylene rubber (EPM), polychloropropene rubber (CR) or natural rubber (NR). Mixtures of these materials can also be considered.

[0022] The application of the coating to the rubber is carried out, for example, by treatments such as spraying, immersion, flow coating, coating, roller coating, brush application or powder coating.

[0023] The invention also relates to a windscreen wiper blade with such a wiping blade. Such windscreen wiper blades for cleaning glass surfaces, in particular vehicle windscreens, are also suitable for cleaning buildings or sensor surfaces. Brief description of the drawings

[0024] The present invention will be described below in more detail with the aid of the attached drawings in which:

[0025] [Fig. 1] diagram of a wiping blade provided with a coating according to the state of the technical,

[0026] [Fig.2] diagram of a wiping blade with a coating according to the invention,

[0027] [Fig.3] diagram of a wiping blade with a coating according to the invention,

[0028] [Fig.4] diagram of a wiping blade coated according to a first method of realization of the invention, and

[0029] [Fig.5] photographic representation of the surface of a wiping blade provided of a coating according to [Fig.4].

[0030] DESCRIPTION OF AN EMBODIMENT

[0031] Figures 1 to 3 schematically show wiping blades provided with coatings serving to describe the technical background on which the invention is based. Thus, [Fig.l] is a diagram of a wiping blade 10 whose surface is provided with a coating of particles 12a of a first particle diameter; these are relatively large particles. The particles 12a are, for example, bound together and to the surface of the wiping blade 10 by a binder 14.

[0032] The coating 16 obtained often has a relatively short abrasion resistance because, on the one hand, the relatively large particles have a large attack surface for mechanical friction and, on the other hand, the content of binder 14 in the coating 16 is relatively low. If, however, the content of binder 14 in the coating 16 is sufficiently high, as is explained schematically in [Fig. 2], the properties of the surface of the coating 16 will be determined mainly by the sliding friction properties of the binder 14. This results, if necessary, in a relatively unsatisfactory wiping result of such a wiper blade 10 provided with the coating 16.

[0033] If, on the other hand, instead of the particles 12a having a first average diameter, particles 12b are selected which have a second, reduced average particle diameter, this results, as shown in [Fig. 3], in a coating 16 whose sliding friction properties certainly depend on the sliding friction properties of the particles 12b; but in such a case, there will not be a coating surface having a structure and flatness of sufficient quality.

[0034] [Fig. 4] shows a wiping blade provided with a coating corresponding to an embodiment of the invention. The wiping blade 20 of this example has a coating 26 of the surface facing the window surface to be cleaned. The coating 26 comprises first particles 22a having a first average diameter and second particles 22b having a second average particle diameter. The coating 26 contains a binder 24. The first and second particles 22a, 22b have different sizes and the ratio between the first and second average particle diameters of the first and second particles 22a, 22b is greater than 2.5, in particular greater than 3.5. The first particles used have, for example, a particle diameter of between 3 and 20 μm and the second particles used have a second particle diameter of between 0.1 and 4 μm.

[0035] The particles 22a, 22b used are for example made of graphite, graphene, polytetrafluoroethylene, polyethylene, polypropylene, molybdenum disulfide and / or tungsten disulfide, the first and second particles 22a, 22b being made of different materials, in particular at least the second particles 22a are made of a fluorinated material or containing fluorine.

[0036] The binder 24 of the coating 26 is for example based on polyacrylate, polyurethane, polystyrene, epoxy, polyester and / or polyether or their mixture, in particular in the form of a copolymer or a copolymer block.

[0037] The binder of the coating 26 is for example a single-component system or a two-component system in which the crosslinking agent of the binder matrix is ​​for example added just before the actual application. The crosslinking agents are for example: carbodiimide, organosiloxane, melamine, amide, phenol, isocyanate and mixtures thereof.

[0038] With such a coating 26, a coated wiping blade 20 is obtained whose surface properties are sufficiently good to obtain, upon cleaning, a glazed surface with a wiping image of sufficient quality.

[0039] [Fig. 5] shows a microscope view of a coating 26 of a wiper blade profile 20. The first and second particles 22a, 22b are recognized, which in this case correspond to a sufficient density of particles with particle diameters of first average diameter and second average diameter for a coating 26 of sufficient quality and long-term durability.

[0040] The wiping blade itself is advantageously, for example, based on ethylene-propylene-diene rubber (EPDM), ethylene propylene rubber (EPM), polychloropropene rubber (CR) or natural rubber (NR). Mixtures of these materials can also be considered.

[0041] The application of the coating to the wiper blade is carried out, for example, by treatments such as spraying, immersion, flow coating, coating, roller coating, brush application or powder coating.

Claims

Claims

1. Wiper blade for a wiper blade of a windscreen wiper comprising a blade base body (20) having a coating (26) of particles (22a, 22b) in particular for reducing friction, wiper blade characterized in that - the coating (26) comprises first particles (22a) having a first average particle diameter and second particles (22b) having a second particle diameter, - the ratio between the first and second average particle diameter is > 2.5 and in particular > 3.

5.

2. A wiping blade according to claim 1, characterized in that at least a portion of the particles (22a, 22b) comprise or are particles of synthetic material.

3. A wiping blade according to claim 2 or 3, characterized in that the first particles (22a) and the second particles (22b) are made of different materials.

4. Wiping blade according to one of the preceding claims, characterized in that the particles (22a, 22b) are made of graphite, graphene, polytetrafluoroethylene, polyethylene, polypropylene, molybdenum disulfide and / or tungsten disulfide.

5. Wiper blade according to one of the preceding claims, characterized in that the first particles (22a) have an average particle diameter of between 3 and 20 pm and the second particles (22b) have an average particle diameter of between 0.1 and 4 pm.

6. Wiper blade according to one of the preceding claims, characterized in that the coating (26) comprises at least one binder (24) in the form of polyacrylate, polyurethane, polystyrene, epoxy, polyester and / or polyether, in particular in the form of a copolymer or a copolymer block.

7. Wiper blade according to one of the preceding claims, characterized in that the coating (26) further contains at least one crosslinking agent in the form of carbodiimide, organosiloxane, melamine, amide, phenolene and / or isocyanate.

8. Wiper blade according to claim 7, characterized in that the binder (24) is in the form of a single-component system.

9. Wiper blade according to one of the preceding claims, characterized in that at least the second particles (22b) are made of a fluorinated or fluoride-containing material.

10. Wiper blade according to one of the preceding claims, characterized in that the base body of the wiper blade (22) comprises a rubber.

11. A wiper blade for a windshield wiper comprising a rubber blade according to one of the preceding claims.

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