FR2988356A1 - Method for manufacturing wiper blade for windshield wiper of vehicle, involves introducing surface structure formed by micro-cavities into partial zone of surface of segment, and applying particles, coating liquid or film on zone of profile - Google Patents

Abstract

The method involves using a profile (10) of a wiper blade (1) having a wiper lip segment (2) and a fixing segment (4). A surface structure formed by a set of micro-cavities (5) in the form of repetitive pattern is introduced into a partial zone of a side surface (2c) of the segment, where the micro-cavities are formed by laser. Particles (6) e.g. thermoplastic polymer particles, coating liquid or film, are applied on partial zone of the wiper blade profile, where the particles have average size depending on average size of the micro-cavities. The partial zone of the profile is heated. An independent claim is also included for a wiper blade.

Description

FIELD OF THE INVENTION The present invention relates to a method of manufacturing a wiper blade, in particular for a windshield wiper and the blade produced by this method and a wiper blade provided with such a wiper blade. State of the art Wiper blade wiper blades are generally designed so that the contour fits a vehicle window and remains flexible at different temperatures.

Compared to other materials such as glass or plastics, however, elastomers have high coefficients of friction which can generate noises during wiping and also cause rapid wear of the wiper blade. It is known to reduce friction by applying thermoplastic particles to the wiper blade by melting these particles if necessary to obtain a friction-reducing layer. In the known methods, however, the particles are applied uncontrollably in a random distribution on the wiper blade, which can result in large variations in the friction-reducing layer. The document DE 10 2009 003 095 A1 describes a method of producing a wiping blade in which a profile is first formed, then vulcanized and after vulcanization, the zone of the profile forming the lip is given. wiping, a laser structure and / or applying a coating of dry lubricant particles which is fixed with a laser. DESCRIPTION AND ADVANTAGES OF THE INVENTION The subject of the present invention is a process for producing a wiper blade, in particular for a wiper comprising: a) using a wiper blade profile having a segment of a wiper blade; wiper lip and securing segment; b) introducing a surface structure formed of a set of micro-cavities into at least a partial area of the wiper blade profile; c) applying particles or a liquid for coating or filming at least a partial area of the wiper blade profile, and d) heating at least a partial area of the wiper blade profile. Microcavities are particularly cavities whose depth and length as well as the width or diameter are less than or equal to 100 gin. At least one partial area of the wiper blade profile is a partial area of the wiper lip segment of the wiper blade profile.

As in process step b), micro-cavities are made in at least a partial area of the wiper blade profile on which in process step c) the coating particles or liquid is applied. or the film and which is heated in the process step d), a particularly strong bond is made between the profile of the wiper blade and the particles or the coating, which gives a very high reliability to the blade wiping. The particles or the coating make it possible to improve the wear resistance and the wiping behavior of the wiper blade and its wiping quality. In particular, a higher and even wear resistance and a low operating noise are thus obtained. The particles may exceed, for example the surface of the wiper blade profile and thus create a lotus effect (super hydrophobic effect) or a hydrophobic effect. Alternatively or additionally, the particles may be of a material reducing the coefficient of adhesion, for example a lubricating material such as graphical, which decreases the friction between the wiper blade and the glass disc. The coating liquid and the film are based on such a material.

In principle, it is also possible to perform steps a) and b) simultaneously or at least directly one behind the other. Thus, for example, a micro-cavity structure can be produced directly when the rubber profile is produced by injection in the profile of the wiper blade or directly after having made the wiper blade profile by extrusion. by printing this structure in the wiper blade profile. The wiper blade profile according to step a) may be extruded or extruded. According to a preferred development, in process step b), the microcavities are produced by means of at least one laser, in particular by laser drilling in the rubber profile. In particular, the wiper blade profile of step a) can be extruded, if necessary, extruded. The process step b) can thus follow in particular the method step a). The laser may be in particular a pulsed laser. In particular, the laser will have a wavelength of up to 1064 nm. The laser is for example a helium-neon laser, a nitrogen laser, an argon-ion laser, a helium-cadmium laser, a crypton-ion laser, an excimer laser, for example a KrF laser, a XeF laser, a laser ArF, XeC1 laser or F2 laser, metal vaporizer, metal-halide laser, Nd: YAG laser or Yb: YAG laser. Laser drilling advantageously makes it possible to produce microcavities with small dimensional variations and in particular having an exact depth and an exact diameter in positions precisely set in the wiper blade profile.

Insofar as particles are applied, they will have a definite position, advantageously in an exact manner thanks to the microcavities which receive the particles. Thus, advantageously, one can even apply particles on a three-dimensional environment.

Even by flowing particles on the microcavities, they particularly tend to hang in or preferably on the microcavities. According to another preferred development, in the process step c), the particles arrive on at least one surface-structured partial area of the wiper blade profile, but with a speed that is sufficiently high for the particles to penetrate partially into the microcavities. Preferably, the speed is chosen nevertheless sufficiently small so that the particles do not penetrate into surface areas without microcavities. Thus, preferably, the size of the microcavities and particles is chosen with respect to each other. The particles can thus be accelerated by a spraying process to arrive at high speed on the partial areas to be provided with microcavities and to penetrate the microcavities and be advantageously already physically connected to the wiper blade profile. In this way, it is even possible to provide particles only one side defined by the microcavities of the wiper blade profile. The appropriate agreement between the size of the microcavities and that of the particles, especially continuously, causes the particles to fill the microcavities and thus protrude from the surface of the rubber profile, which offers a particularly elegant possibility of producing a surface having hydrophobic characteristics (lotus effect, super hydrophobic effect) particularly good and precisely adjustable. Preferably, the process step d) is performed so that the particles essentially retain their shape. According to another preferred development, in process step d), only at least a partial region of the wiper blade profile is heated so that the particles essentially retain their shape, which ensures that the particles participate in the wiper blade profile. the lotus effect. According to another preferred development, in the process step d), at least a partial region of the wiper blade profile is heated, but, however, so that the particles melt together to form a substantially continuous layer. This makes it possible to advantageously produce, for example, a coating which reduces friction. According to another development, in process step c), at least a partial area of the wiper blade profile is coated with a thermosetting coating liquid. According to another development, in process step c), a film, especially a thermoplastic film, is rolled onto at least a partial region of the wiper blade profile. To the extent that the particles are melted in process step d) or a coating liquid or film is applied in process step c), then microcavities performed at defined locations exactly, advantageously participate in the connection between the wiper blade profile and the coating. By heating and then in process step d), the physical connection between the wiper blade profile and the particles or coating can be strengthened and, where appropriate, a chemical bond can be developed between the material of the wiper profile. wiper blade and that of particles or coating. In particular, it is possible in process step d) to heat the entire wiper blade profile. According to a preferred development, in process step a), an unvulcanized or at least only partly vulcanized wiper blade profile is used, especially an unvulcanized wiper blade profile. In step d), it is possible to vulcanize the wiper blade profile or at least terminate the vulcanization and in particular to vulcanize it.

The heating in process step d) can be done by vulcanizing at least a partial area of the wiper blade profile, for example the complete profile of the wiper blade. The vulcanization can be done in particular using a heat treatment medium, for example using a bath of molten salt. The bath of molten salt may be for example a bath formed of a mixture of potassium nitrate and / or sodium nitrate and / or sodium nitrite and / or lithium nitrite. The vulcanization will be done for example at a temperature in the range 150 ° C - 300 ° C. According to another development, the microcavities have a mean diameter or a mean length or an average width of the order of 5 gm up to 50 gm, for example from 5 gm up to 40 gm. The microcavities will for example have an average depth of the order of 1 gm up to 25 gm, for example between 1 gm up to 20 gm. Such dimensioning of the microcavities is, for example, advantageous if, in process step c), the particles having an average particle size of the order of 5 gm up to 50 gm, for example 5 gm up to 40 g, are used. gm. To obtain a lotus effect, it is advantageous to size the microcavities and particles so that the particles fill the microcavities and protrude from the surface of the wiper blade profile by 5 gm up to 20 gm. Such dimensioning has, however, also been advantageous in that in the coating step c), a coating liquid or a film is applied. According to another development, the average distance between the microcavities is in a range such as 5 gin to 100 gm, for example 5 gm up to 60 gin. In order to have a lotus effect, it is advantageous that the average distance between the microcavities is chosen in the range from 5 to 50 gin. According to another development, in process step c), particles whose average size is tuned according to the average size of the microcavities are applied. In particular, the average size of the particles will be adapted to the average size of the microcavities so that the particles fill the microcavities and protrude from the surface of the wiper blade profile by a distance, for example 5 gm up to 20 gin . The average diameter or the average length or the average width of the microcavities essentially correspond to the average diameter of the particles and / or the average depth of the microstructures will be substantially greater than or equal to the average diameter, in particular to the radius of the particles.

According to another development, the microcavities are in the form of a pattern, in particular a repetitive pattern. The pattern may in particular be symmetrical and / or be realized so that the microcavities are distributed in a homogeneous and / or equidistant manner. According to a preferred development, the particles are polymer particles, in particular thermoplastic polymer particles. In particular, the polymer particles are in particular thermoplastic polymer particles. The polymer particles will perform during the process step d), advantageously, a physical and / or chemical bond with the wiper blade profile.

The particles may for example be ultra-high density polyethylene (UHMW-PE) particles, high density polyethylene (HD-PE) particles, low density polyethylene (LD-PE) particles, isotactic polypropylene particles (PP). ) polyamide particles (PA), polytetrafluoroethylene (PTFE) particles, or a mixture of these materials. In particular, the polyolefin particles may be crystalline particles of polyolefin, especially ultra-high density polyethylene particles (UHMW-PE). For example, particles marketed under the MIPELON trademark of Mitsui Chemicals and which are ultra-high density polyethylene (UHMW-PE) may be used. The particles may, however, also be friction-reducing particles, such as inorganic friction-reducing particles, such as, for example, carbon black particles, graphite particles, molybdenum disulfide particles and / or particulates. silicate. The wiper blade profile will be an elastomer or will be made with an elastomer. The elastomer may be selected from the group consisting of ethylene-propylene-diene monomer rubber (EPDM), ethylene-propylene-monomer rubber (EPM), chlorobutyl rubber, bromobutyl rubber, chloroprene rubber (CR), natural rubber (NR), polyurethane rubber or combinations thereof. In particular, the profile of the wiper blade may be based on polyolefins. According to another development, in process step d), the surface microstructure formed of microcavities is made in at least a partial region of the wiper lip segment of the wiper blade profile. In particular, in process step b), the surface structure can be produced with microcavities, in particular in the partial area of the lateral surface of the wiping lip segment of the wiper blade profile, these partial zones. arriving to the edges of the wiper blade to achieve. According to another preferred development, the wiper blade profile is a double wiper blade profile whose surface of the section corresponds to the surface of the section of two wiper blades connected to one another. other by the two segments of wiping lip. The double wiper blade profile can be produced in particular in the form of a bead, for example an extruded bead. The method comprises in particular the following step: e) separating the double wiper blade profile into simple blades. The double wiper blade profile may be separated, for example in particular horizontally, in particular between the two segments of the wiping lip. Insofar as the double wiper blade profile is in the form of a bead, it may in particular be cut several times perpendicular to the longitudinal extension of the bead to produce for example many wiper blades. For other technical features and advantages of the method of the invention, reference will be made explicitly to the descriptions in connection with the wiper blade according to the invention and the wiper blade, and to the figures.

Other objects of the invention are the wiper blade and a wiper blade equipped with such a wiper blade. The wiper blade is in particular made according to the method of the invention. The wiper blade comprises a base body of which at least a partial area is structured by a set of microcavities. In particular, at least a partial area of the wiping lip segment of the base body of the wiper blade will be structured by microcavities. For example, the microcavities may be made at least in partial areas of the side surfaces of the wipe lip segment of the wiper blade profile, these surfaces being adjacent to the wiping edges of the wiper blade. According to a development, the microcavities are partially or completely filled with particles which in particular protrude from the surface of at least a partial area of the wiper blade base body. Since the microcavities are filled with particles, a solid bond is advantageously made between the sponge base body and the coating. As the particles thus protrude from the surface of at least a partial area of the wiper blade base body, a super hydrophobic lotus effect is advantageously also provided.

According to another development, the surface of at least a partial area of the wiper blade base body is provided / covered with a coating which partially or completely fills the microcavities. As the microcavities are filled with the coating, a strong bond is advantageously made between the wiper blade base body and the coating.

The microcavities have a mean diameter or average length or average width ranging from 5 gm up to 50 gm, for example 5 gm up to 40 gm. The microcavities will for example have an average depth which is in a range such that 1 gm up to 25 gin, for example 1 gin up to 20 gm. The particles will have, for example, an average size in a range such as 5 gm up to 50 gm, for example a range of gin up to 40 gin. Preferably, the particles partially or completely fill the microcavities and thus pass from the surface of the wiper blade profile from a height in a range of 5 gm up to 20 gin. By way of example, the average diameter or the average length or the average width of the microcavities corresponds essentially to the mean diameter of the particles and / or to the average depth of microstructures being essentially smaller than or equal to the average diameter, in particular to the radius. particles. The average distance between the microcavities is for example in a range such as 5 gm up to 100 gin and for example a range such as 5 gm up to 60 gm.

The microcavities preferably have the form of a repeating pattern. The pattern is in particular symmetrical and / or designed so that the microcavities are distributed in a homogeneous and / or equidistant manner. The particles comprise or are in particular polymer particles, for example thermoplastic polymer particles. The particles may for example be ultra-high density polyethylene (UHMW-PE) particles, high density polyethylene (HD-PE) particles, low density polyethylene (LD-PE) particles, isotactic polypropylene particles (PP). ) polyamide particles (PA), polytetrafluoroethylene (PTFE) particles, or a mixture of these materials. In particular, the polyolefin particles may be crystalline particles of polyolefin, especially particles of ultra-high density polyethylene (UHMWPE). For example, it will be possible to use particles sold under the MIPELON trademark of Mitsui Chemicals and which are ultra-high density polyethylene (UHMW-PE).

The particles may also be friction-reducing particles, for example inorganic friction-reducing particles, such as carbon black particles, graphite particles, molybdenum disulfide particles and / or silicate particles. The basic body of the wiper blade comprises in particular at least one elastomer or is made of elastomer, for example, the elastomer may be chosen from the group comprising ethylene-propylene-diene-monomer rubber (EPDM), rubber ethylene-propylene-monomer (EPM), chlorobutyl rubber, bromobutyl rubber, chloroprene rubber (CR), natural rubber (NR), polyurethane rubber or combinations thereof. In particular, the profile of the wiper blade may be based on polyolefins.

Drawings The present invention will be described in more detail below with the aid of embodiments of the method and a wiper blade shown in the accompanying drawings in which: - Figure 1 is an image made by a microscope surface-scanning electronics of a wiper blade profile in which a pattern of microcavities has been applied by laser drilling; FIG. 2a is a schematic top view of a pattern of micro-cavities filled with 2b is a schematic section of the wiper blade profile of FIG. 2a, FIG. 2c is a schematic section of the wiper blade profile of FIG. have been melted together to give a substantially continuous layer; FIG. 3 is a schematic section of a wiper blade.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION FIG. 1 is an image of a wiper blade profile 1 made by a surface scanning electron microscope; the pattern of microcavities 5 was made in the blade by laser drilling. The microcavities 5 have an average diameter of less than or equal to 10 μm, in particular of the order of 6 μm. Figure 1 shows that the micro-cavity pattern 5 is repetitive and symmetrical. The microcavities are distributed essentially homogeneously and essentially equidistantly. Figure 1 shows the wiper blade profile after applying process step b).

Figure 2a is a view similar to that of Figure 1 but schematically. FIG. 2a shows how the wiper blade profile 1 is formed after forming according to process step c), with particles 6 applied to the profile of the wiper blade 1. The average particle size 6 is defined according to the average size of the microcavities 5 so that the particles 6 fill the microcavities 5 already achieving a strong physical connection between the wiper blade profile 1 and the particles 6. Figure 2b shows that the particles 6 at the same time protrude from the surface of the rubber blade profile 1. The other surface areas of the rubber blade profile 1 have no particles 6. This is realized for example in that in the process step c ), the particles 6 are sprayed, for example by means of a nozzle on the wiper blade profile 1, so that they arrive on the wiper blade profile 1 with a speed sufficient for the particles 6 penetrate partially into the m i-crocavities 5 but not in the other surface areas of the wiper blade profile 1. After such a spraying operation, any residual free particles 6 may be removed in a simple manner, for example by scraping, washing , blowing, to disengage them from the surface of the wiper blade profile 1.

Then, the wiper blade profile 1 is heated in the context of the implementation of the method step d) to improve a physical and / or chemical connection between the wiper blade profile 1 and the particles 6 Advantageously, in process step d), the material of the wiper blade profile 1 can be vulcanized at the same time. For example, the process step d) can be carried out in a transfer medium. heat, for example in a bath of liquid salt. FIG. 2b shows that this is done in the context of an embodiment of process step d) of heating so that the particles 6 substantially retain their shape. This is achieved by using heat-insensitive particles or heat-sensitive particles, for example thermoplastic polymer particles, so that at the set temperature of the process step ), the particles 6 soften but do not melt. This embodiment provides a lotus effect to the surface of the wiper blade profile 1. In addition, the material of the particles 6 may have hydrophobic characteristics and / or serve as a lubricant. FIG. 2c shows that the heating in another embodiment of process step d) consists in melting the particles 6 to obtain a substantially continuous thin coating 6. The thin coating 6 thus covers not only the surface of the wiper blade profile 1, but it also fills the microcavities 6, which results in a particularly strong and strong connection between the wiper blade profile 1 and the coating Figure 3 is a section of a wiper blade 10 made using the method of the invention. FIG. 3 shows that the wiper blade 10 has a base body 1 having a wiping lip segment 2 connected by a tilting segment 3 to an attachment segment 4. FIG. 3 shows that the lip segment of FIG. wiper 2 has two wiping edges 2a between which there is a front surface 2b at which each time a side surface 2c arrives. In addition, the two wiping edges 2a of the wiping lip segment 2, in particular the zones of the two lateral surfaces 2c adjacent to the wiping edges 2a, participate in the wiping function of the wiper blade 10. It has been found particularly advantageous that the side surfaces 2c of the wiping lip segment 2 are provided with a functional layer 6, for example a water repelling layer or other layer 6 reducing friction. . FIG. 3 shows that the partial areas of the lateral surfaces 2c of the wiping lip segment 2 adjacent to the wiping edges 2a, each have a functional layer 6 with micro-cavities 5 as described in FIGS. 2a-2c and particles 6 filling the microcavities or microcavities 5 and a coating 6 filling the microcavities.35 NOMENCLATURE OF THE MAIN ELEMENTS 1 wiper blade profile 2 wiping lip segment 2a wiping edge 2b front surface 2c side surface 3 segment d tilting spacer 4 fixing segment 5 microcavities 6 particles 10 wiper blade15

Claims (14)

CLAIMS 1 °) A method of producing a wiper blade (10), in particular for a wiper comprising the following steps: a) using a wiper blade profile (10) having a lip segment of wiping (2) and a fixing segment (4), b) introducing a surface structure formed of a set of micro-cavities (5) into at least a partial area (2c) of the wiper blade profile (1). ), c) applying particles (6) or a coating liquid or a film to at least one partial area (2c) of the wiper blade profile (1), and d) heating at least a partial area (2c) the wiper blade profile (1). 2) Method according to claim 1, characterized in that in the method step b), the microcavities (5) are made using a laser. 3) Method according to claim 1, characterized in that the microcavities have a diameter in a range between 5 gm up to 50 gm. 4) Method according to claim 1, characterized in that the average distance between the microcavities (5) is in a range such that 5 gm up to 100 gm. 5) Method according to claim 1, characterized in that in the process step c), particles (6) are applied whose average size depends on the average size of the microcavities (5) and in particular whose average size of particles is adapted to the average size of microcavities so that the particles fill the mid-crocavities and exceed the surface of the wiper blade profile, in particular 5 gm up to 20 gm. 6 °) Method according to claim 1, characterized in that the microcavities (5) are in the form of a pattern, including a repeating pattern. 7) Method according to claim 1, characterized in that the particles (6) are polymer particles, in particular thermoplastic polymer particles. Process according to Claim 1, characterized in that in the process step c), the particles (6) arrive on at least one partial area (2c) of the wiper blade profile (1) with a speed sufficiently high for the particles (6) to penetrate partially into the microcavities (5). Process according to Claim 1, characterized in that in step d) at least one partial zone (2c) of the wiper blade profile (1) is heated so that the particles (6) which have have been essentially shaped, or - in process step d), at least one partial region (2c) of the wiper blade profile (1) is heated for the particles (6) to be applied. , melt to form a substantially continuous layer. Process according to Claim 1, characterized in that in the process step c) at least one partial area (2c) of the wiper blade profile (1) is provided with a liquid thermosetting coating, or in process step c), a thermoplastic film is rolled onto at least one partial region (2c) of the wiper blade profile (1). Process according to Claim 1, characterized in that - in process step a), a non-vulcanized or at least only partly vulcanized wiper blade profile is used, and - in the process step of ), the wiper blade profile (1) is vulcanized or at least cured. 12 °) Method according to claim 1, characterized in that in the method step a), the wiper blade profile (1) is produced by extrusion. Method according to Claim 1, characterized in that in process step b) the surface structure consisting of microcavities (5) is formed in at least one partial area (2c) of the wiping lip segment. (2) of the wiper blade profile (1), in particular at least in the partial areas (2c) of the side surfaces of the wiping lip segment (2) of the wiping blade profile (1) which are adjacent at the wiping edges (2a) of the wiper blade (10) to be produced. 14 °) Method according to claim 1, characterized in that the wiper blade profile (10) is a double profile wiper blade whose cross-sectional area corresponds to that of two wiper blades ( 10) connected to one another by the two wiper lip segments (2) and in particular the method further comprises the step e) of separating the double wiper blade profile into blades wiper blade (10) .15 °) Wiper blade, in particular made according to a process of any one of claims 1 to 14, comprising a wiper blade base body (1) of which at least a partial zone (2c) is structured by a set of microcavities (5), the microcavities (5) being filled partially or totally with microparticles (6) which in particular protrude from the surface of at least one partial zone (2c) of the body of wiper blade base (1) or the surface of at least a partial area (2c) of the wiper blade base body (1) is provided with a coating (6) which partially or completely fills the microcavities (5).