BE1021337B1 - MESH PRODUCTION BY MICROVERTING - Google Patents

Abstract

The present invention relates to a method for producing a wiper rubber (10), in particular for a windshield wiper. In this case, a wiper rubber profile (1) is initially provided in a method step a), which has a wiper lip section (2) and a fastening section (4). In order to increase the service life of the wiper rubber (10) and to improve its wiping behavior and wiping quality, in a method step b) a surface structuring made up of a plurality of micro-depressions (5) is introduced into at least one partial area (2c) of the wiper rubber profile (1); In a method step c), particles (6) or a coating liquid or a film are applied to the at least one partial area (2c) of the wiper rubber profile (1); and in a method step d) at least the at least one sub-area (2c) of the wiper rubber profile (1) is heated. The present invention also relates to a corresponding wiper rubber (10) and a windshield wiper equipped therewith.

Description

Wischgummi production by means of microwells

The present invention relates to a method for producing a wiper blade, a corresponding squeegee and a wiper equipped therewith.

State of the art

Wiper blades for windshield wipers are usually designed to adapt to the contour of a glass pane of a vehicle and to remain flexible at different temperatures. ·

However, compared to other materials, such as glass or plastic, elastomers have high coefficients of sliding friction, which can cause noise during wiping and wiping rubber wears quickly.

It is known to apply to reduce the sliding friction thermoplastic particles on the squeegee and, where appropriate, melt together to form a friction-friction-reducing layer. In the known methods, however, the particles are applied uncontrollably in a random distribution to the squeegee, which can lead to significant fluctuations within the friction-reducing layer.

DE 10 2009 003 095 A1 describes a method for producing a wiper blade in which a profile is first formed and then vulcanized, wherein a region of the profile which forms the wiper lip is structured with a laser after vulcanization on the surface and / or coated with dry lubricant particles which are fixed with a laser.

Disclosure of the invention

The present invention is a process for producing a wiper blade rubber, in particular for a (vehicle) windscreen wiper.

In this case, in a method step a) a wiper rubber profile is provided, which has a wiper lip section and a fastening section.

In a method step b), a surface structuring of a plurality of microwells is introduced into at least a portion of the squeegee profile.

In a method step c), particles or a coating liquid or a film are applied to the at least one subregion of the wiper rubber profile.

And in a method step d), at least the at least one subregion of the squeegee profile is heated.

Under microwells can be understood in particular wells whose depth and whose length and width or diameter is less than or equal to 100 pm '.

The at least one subregion of the wiper rubber professional may in particular be at least one subregion of the wiper lip section of the wiper rubber profile.

Characterized in that in step b) the microwells are introduced into at least a portion of the squeegee profile on which in process step c) the particles or the coating liquid or the film is / is applied and which in step d) is heated, can advantageously a a particularly strong bond between the squeegee profile and the particles or the coating and thus a long service life of the wiper blade can be achieved. The wear resistance and the wiping behavior of the wiper blade rubber as well as the wiping quality of the wiper blade rubber can be improved by the particles or the coating. In particular, a more even and higher wear resistance and a lower noise during wiping can be achieved.

The particles can, for example, project beyond the surface of the wiper rubber profile and thereby cause a lotus effect or hydrophobic properties.

Alternatively or additionally, the particles may be formed of a friction-reducing material, for example a lubricant, for example graphite, which reduces the sliding friction between the squeegee and a glass sheet.

Such a material may also be based on the coating liquid and the film.

In principle, it is possible to carry out the method steps a) and b) jointly or at least in quick succession. Thus, for example, it is possible to introduce the microwells directly into the squeegee profile by injection molding directly upon provision of the squeegee profile, or by extrusion into the squeegee profile, for example, directly after provision of the squeegee profile. However, the squeegee profile in method step a) can also be extruded or provided by extrusion.

Within the scope of a preferred embodiment, in step b) the microwells are introduced into the squeegee profile by at least one laser, in particular by laser drilling. In particular, the squeegee profile can be extruded in process step a) or provided by extrusion. Process step b) can be carried out in particular according to process step a). The laser can be in particular a pulsed laser. In particular, the laser may have a wavelength of up to 1064 nm. For example, the laser may be a helium-neon laser, a nitrogen laser, an argon-ion laser, a helium-cadmiun laser, a krypton-ion laser, an excimer laser, for example, a KrF laser, XeF laser, ArF Laser, XeCl laser or F2 laser,. a metal vapor laser, a metal halide laser, a Nd: YAG laser or a Yb: YAG laser.

So-called laser drilling advantageously allows microwells with small dimensional variations, in particular with an exact depth and. a precise diameter to introduce at precisely adjustable positions in the squeegee profile.

Insofar as particles are applied, it is advantageously possible for the microwells to predetermine precisely defined locations which are to be provided with particles. Thus, advantageously even a three-dimensional environment can be specifically provided with particles.

Even when trickling particles on the microwells, they tend to prefer to stick in or on the microwells.

Within the scope of a further preferred embodiment, however, in method step c), the particles impinge on the at least one surface-structured subregion of the squeegee profile at a speed which is sufficiently high that the particles partly penetrate into the microwells. Preferably, however, the speed is chosen low enough that the particles can not penetrate into the microfuge-free surface areas. In this case, the size of the microwells and the particles are preferably matched. The particles can be accelerated, for example by means of a spraying process, at a high speed onto the subsections provided with the microwells and penetrate into the microwells and thus advantageously already physically connected to the wiper blade profile. In this way, it is even possible to provide the squeegee profile only at the points with particles which are predetermined by the microwells. By suitably adjusting the size of the microwells and the particles, in particular to the extent that the particles fill the microwells and thereby project beyond the surface of the squeegee profile, this offers a particularly elegant possibility a surface with particularly good and precisely adjustable hydrophobic properties (lotus effect ).

Preferably, process step d) is carried out in such a way that the particles essentially retain their shape.

In a further preferred embodiment, therefore, in method step d), the at least one subregion of the squeegee profile is (only) heated in such a way that the particles essentially retain their shape. This ensures that the particles contribute to a lotus effect.

In the context of another preferred embodiment, in process step d) the at least one subregion of the squeegee profile is heated, however, such that the particles fuse together to form a substantially continuous layer. Thus, advantageously, for example, a friction-reducing, coating can be realized.

In a further embodiment, in process step c), the at least one subregion of the squeegee profile is coated with a heat-curable coating liquid.

Within the scope of a further embodiment, in process step c), in particular a thermoplastic film is laminated onto the at least one subregion of the squeegee profile.

Also inasmuch as the particles are melted in process step d) or a coating liquid or a film is applied in process step c), micro-depressions introduced at precisely defined locations advantageously have an effect on the bond between the wiper rubber profile and the coating.

By the subsequent heating in method step d), the physical connection between the wiper rubber profile and the particles or coating can be intensified and optionally additionally a chemical bond can be formed between the material of the wiper rubber profile and the material of the particles or the coating. It is particularly possible in process step d) to heat the entire squeegee profile.

In a preferred embodiment, an unvulcanized or at least only partially vulcanized, in particular an unvulcanized, squeegee profile is provided in method step a). In process step d), the squeegee profile can then be vulcanized or at least vulcanized, in particular vulcanized.

The heating in process step d) can be carried out in particular by vulcanizing the at least one subregion of the wiper rubber profile, for example the complete wiper rubber profile.

The vulcanization can be carried out in particular by means of a heat treatment medium, for example by means of a liquid salt bath. The liquid salt bath may, for example, be a melt containing, for example, a mixture of potassium nitrate and / or sodium nitrate and / or sodium nitrite and / or lithium nitrite. The vulcanization can be carried out, for example, at a temperature in a temperature range of 150 150 ° C to 300 300 ° C.

In a further embodiment, the microwells have an average diameter or an average length and average width in a range of ^ 5 μπι to ^ 50 μπι, for example, from ^ 5 μπ \ to ^ 40 μπι on. The microwells, for example, an average depth in a range of ^ 1 μπι to ^ 25 μπι, for example, from ^ 1 μιη to ^ 20 μπι have. Such a dimensioning of the microwells may be advantageous, for example, if in method step c) particles having an average particle size in a range of ^ 5 pm to ^ 50 μπι, for example, from ^ 5 pm to ^ 40 μπι used. To achieve a Lotus effect, it has proven to be advantageous to choose the dimensioning of the microwells and the particles such that the particles fill the microwells and thereby exceed the surface of the squeegee profile by ^ 5 μιη to ^ 20 μιη. However, such a dimensioning has also proved advantageous insofar as a coating liquid or film is applied in method step c).

In a further embodiment, the average distance between the microwells in a range of ^ 5 μιη to ^ 100 μιη, for example, from ^ 5 μπι to ^ 60 μιη. To achieve a lotus effect, it has proven to be advantageous to choose the average distance between the microwells so that it is in a range of ^ 5 μιη to ^ 50 μπι.

Within the scope of a further embodiment, particles are applied in method step c) whose average size is matched to the average size of the microwells. In particular, the average size of the particles may be adapted to the average size of the microwells so that the particles can fill the microwells and thereby project beyond the surface of the wiper-rubber profile, for example by .mu.m to .mu.m.sup.2 .mu.m. For example, the average diameter or average length and width of the microwells may be substantially equal to the average diameter of the particles and / or the average depth of the microstructures may be substantially less than or equal to the average diameter, particularly radius, of the particles.

In a further embodiment, the microwells are in the form of a, in particular repetitive, pattern formed. The pattern may in particular be symmetrical and / or configured such that the microwells are distributed homogeneously and / or equidistant from each other.

Within the scope of a preferred embodiment, the particles comprise polymer particles, in particular thermoplastic polymer particles. In particular, the particles may be polymer particles, in particular thermoplastic polymer particles. Polymer particles can advantageously undergo physical and / or chemical bonding with the squeegee profile during process step d). For example, the particles may include ultrahigh molecular weight polyethylene (UHMW-PE) particles, high density polyethylene (HDPE) particles, low density polyethylene (LD-PE) particles, isotactic polypropylene (PP) particles, polyamide particles (PA) particles. In particular, the particles may be polyolefin particles, for example crystalline polyolefin particles, in particular ultrahigh molecular weight polyethylene (UHMW-PE) particles For example, ultrahigh molecular weight particles marketed under the trade name MIPELON by Mitsui Chemicals may be used Polyethylene (UHMW-PE) can be used.

However, the particles can also comprise or be friction-reducing particles, for example inorganic friction-reducing particles, for example soot particles, graphite particles, molybdenum disulfide particles and / or silicate particles.

The squeegee profile may in particular comprise or be formed from at least one elastomeric material. For example, the elastomeric material 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 and combinations thereof. In particular, the squeegee profile may be polyolefin-based.

Within the scope of a further preferred embodiment, in step b) the surface structuring of microwells is introduced into at least one subregion of the wiper lip section of the wiper rubber profile. In particular, in method step b), the surface structuring of micro-depressions can be introduced at least into partial regions of the side surfaces of the wiper lip section of the wiper rubber profile which adjoin the wiping edges of the wiper rubber to be formed.

In the context of a further preferred embodiment, the squeegee profile is a squeegee double profile whose cross-sectional area corresponds to the cross-sectional area of two squeegee rubbers which are connected to one another via the two wiper lip sections. The squeegee double profile can be designed in particular in the form of a strand, for example an extrusion strand. In this case, the method can, in particular, furthermore comprise the method step: e): separating the wiper-rubber double profile into individual wiper rubbers. The squeegee double profile can be separated, for example, in particular horizontally, between the two wiper lip sections. Inasmuch as the squeegee double profile is designed in the form of a strand, the strand can also be separated, in particular several times, perpendicular to the longitudinal extent of the squeegee string, for example in order to produce a large number of squeegees.

With regard to further technical features and advantages of the method according to the invention, reference is hereby explicitly made to the explanations in connection with the squeegee and wiper according to the invention and with the figures.

Further objects of the present invention are a squeegee and a windscreen wiper comprising such a squeegee. The squeegee may in particular be produced by a method according to the invention.

The squeegee comprises a squeegee body of which at least a portion is structured by a plurality of microwells. In particular, at least one subregion of the wiper lip section of the wiper rubber base body can be structured by the microwells. For example, the microwells may be introduced at least into subareas of the side surfaces of the wiper lip section of the squeegee profile which adjoin the wiping edges of the squeegee.

In one embodiment, the microwells are partially or completely filled with particles, in particular which project beyond the surface of the at least one subregion of the wiper rubber base body. Because the microwells are filled with the particles, it is advantageously possible to realize a stable bond between the wiper rubber base body and the coating. Due to the fact that the particles project beyond the surface of the at least one subregion of the wiper rubber base body, a hydrophobic lotus effect can also advantageously be achieved.

In the context of another embodiment, the surface of the at least one subregion of the wiper rubber base body is provided / covered with a coating which partially or completely fills the microwells. Because the microwells are filled with the coating, it is advantageously possible to realize a stable bond between the wiper rubber base body and the coating.

The microwells may have an average diameter or an average length and average width in a range of from 5 pm to 50 pm, for example from 5 pm to 40 pm. For example, the microwells may have an average depth in a range from 1 pm to 25 pm, for example from 1 pm to 20 pm. The particles may, for example, have an average particle size in a range of from 5 pm to 50 pm, for example from 5 pm to 40 pm. Preferably, the particles fill the microwells partially or completely and thereby exceed the surface of the squeegee profile by ^ 5 pm to ^ 20 pm. For example, the average diameter or average length and width of the microwells may be substantially equal to the average diameter of the particles and / or the average depth of the microstructures may be substantially less than or equal to the average diameter, particularly radius, of the particles.

The average distance between the microwells may be in a range of ^ 5 μιη to ^ 100 μπι, for example, from ^ 5 μπι to ^ 60 μη, lie.

The microwells are preferably in the form of a, in particular repetitive, pattern formed. The pattern may in particular be symmetrical and / or configured such that the microwells are distributed homogeneously and / or equidistant from each other.

The particles may in particular comprise or be polymer particles, for example thermoplastic polymer particles. For example, the particles may include ultrahigh molecular weight polyethylene (UHMW-PE) particles, high density polyethylene (HDPE) particles, low density polyethylene (LD-PE) particles, isotactic polypropylene (PP) particles, polyamide particles (PA) particles, Polytetrafluoroethylene particles (PTFE) or a mixture thereof include or be. In particular, the particles may be polyolefin particles, for example crystalline polyolefin particles, in particular ultrahigh molecular weight polyethylene (UHMW-PE) particles. For example, particles of ultra-high molecular weight polyethylene (UHMW-PE) marketed under the trade name MIPELON by Mitsui Chemicals can be used.

However, the particles can also comprise or be friction-reducing particles, for example inorganic friction-reducing particles, for example soot particles, graphite particles, molybdenum disulfide particles and / or silicate particles.

The wiper rubber base body may in particular comprise or be formed from at least one elastomeric material. For example, the elastomeric material 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 and combinations thereof. In particular, the squeegee profile may be polyolefin-based.

With regard to further technical features and advantages of the wiper rubber and windscreen wiper according to the invention, reference is hereby explicitly made to the explanations in connection with the method according to the invention and with the figures.

drawings

Further advantages and advantageous embodiments of the subject invention are illustrated by the drawings and explained in the following description. It should be noted that the drawings have only descriptive character and are not intended to limit the invention in any way. Show it

Figure 1 is a scanning electron micrograph of a squeegee profile into which a pattern of microwells was introduced by means of laser drilling.

Figure 2a is a schematic plan view of a squeegee profile with a pattern of microwells filled with particles projecting above the surface;

FIG. 2b shows a schematic cross section through the wiper rubber profile shown in FIG. 2a; FIG.

FIG. 2c shows a schematic cross section through the squeegee profile shown in FIG. 2b, wherein the particles have been melted together to form a substantially continuous layer; and Fig. 3 is a schematic cross section through a

squeegee

I

Figure 1 shows a scanning electron micrograph of a squeegee profile 1, in which a pattern of microwells 5 was introduced by means of laser drilling. The microwells 5 have an average diameter of ^ 10 ym, in particular of about 6 ym, on. FIG. 1 shows that the pattern of microwells 5 is repeated and symmetrical. The microwells are substantially homogeneously distributed and formed substantially equidistant from each other. Figure 1 illustrates how the squeegee profile can be configured after performing an embodiment of method step b).

FIG. 2 a shows a schematic view similar to FIG. 1. FIG. 2 a illustrates how the squeegee profile 1 can be configured after carrying out an embodiment of method step c) in which particles 6 have been applied to the squeegee profile 1 whose mean size is matched to the average size of the microwells 5 in that the particles 6 fill the microwells 6, which already results in a strong physical connection between the squeegee profile 1 and the particles 6. FIG. 2 b illustrates that the particles 6 at the same time project beyond the surface of the wiper-rubber profile 1. The remaining surface areas of the squeegee profile 1 have no particles 6.

This can be achieved, for example, by the fact that in method step c) the particles 6 are sprayed onto the squeegee profile 1, for example, by means of a nozzle and impinge on the squeegee profile 1 at a speed which is sufficiently high that the particles 6 partially penetrate into the microwells 5 but not in the other surface areas of the squeegee profile 1. After such spraying optionally remaining loose particles 6 can be removed from the surface of the squeegee profile 1 in a simple manner, for example by stripping, washing or blowing off.

Thereafter, the squeegee profile 1 is heated in an embodiment of method step d) in order to further improve a physical and / or chemical connection between the squeegee profile 1 and the particles 6. Advantageously, the material of the squeegee profile 1 can be vulcanized simultaneously in process step d). For example, process step d) can be carried out in a heat transport medium, for example in a liquid salt bath.

FIG. 2b illustrates that in the context of an embodiment of method step d), the heating takes place in such a way that the particles 6 essentially retain their shape. This can be achieved either by using heat-insensitive particles 6 or by using heat-sensitive particles 6, for example thermoplastic polymer particles, the temperature in process step d) being set such that the particles 6 soften but do not melt. By this embodiment, the surface of the squeegee profile 1 can advantageously be provided with a lotus effect. In addition, the material of the

Particles 6 have hydrophobic properties and / or serve as a lubricant.

FIG. 2 c illustrates that the heating in another embodiment of method step d) takes place in such a way that the particles 6 melt together to form a substantially continuous, thin coating 6. The thin coating 6 not only covers the surface of the squeegee profile 1, but also fills the microwells 6, resulting in a particularly stable and durable composites between the squeegee profile 1 and the coating 6.

FIG. 3 shows a squeegee 10 which can be produced by the method according to the invention. FIG. 3 illustrates that squeegee 10 comprises a squeegee base body 1 which has a squeegee section 2 which is connected to a mounting section 4 via a tilting web section 3. FIG. 3 illustrates that the wiper lip section 2 has two wiping edges 2a, between which an end face 2b is formed and to which a respective side face 2c adjoins. In addition to the two wiping edges 2a of the wiper lip section 2, the subregions of the two side faces 2c, which adjoin the wiping edges 2a, are involved in the wiping function of the wiper blade rubber 10. It has proven to be advantageous, in particular, to provide the side surfaces 2c of the wiper lip section 2 with a functional layer 6, for example a water-repellent or other, friction-friction-reducing layer 6.

FIG. 3 illustrates that the subareas of the side surfaces 2c of the wiper lip section 2 adjoining the wiping edges 2a each have a functional layer 6 which, as explained in FIGS. 2a to 2c, is based on microwells 5 and the microwells filling the microwells 6 and microwells 5 and one Micro-wells filling coating 6 based.

Claims (15)

claims 1. A method for producing a wiper blade rubber (10), in particular for a windscreen wiper, comprising the method steps: a) providing a squeegee profile (1) with a wiper lip section (2) and a fastening section (4); b) introducing a surface structuring of a plurality of micro-recesses (5) in at least a portion of (2c) of the squeegee profile (1); c) applying particles (6) or a coating liquid or a film to the at least one portion (2c) of the squeegee profile (1); and d) heating at least the at least one subregion (2c) of the squeegee profile (1). 2. The method of claim 1, wherein in step b) the microwells (5) are introduced by at least one laser. 3. The method of claim 1 or 2, wherein the microwells (5) have an average diameter in a range of ^ 5 μια to ^ 50 pm. 4. The method according to any one of claims 1 to 3, wherein the average distance between the microwells (5) in a range of ^ 5 pm to ^ 100 pm. 5. The method according to any one of claims 1 to 4, wherein in step c) particles (6) are applied, the average size of the average size of. Micro-pits (5) is tuned, in particular wherein the average size of the particles, is adapted to the average size of the microwells that the particles fill the microwells, while the surface of the squeegee profile, in particular by ^ 5 p to ^ 20 μπι, overtop. 6. The method according to any one of claims 1 to 5, wherein the microwells (5) in the form of a, in particular repetitive, pattern are formed. 7. The method according to any one of claims 1 to 6, wherein the particles (6) are polymer particles, in particular thermoplastic polymer particles. 8. The method according to any one of claims 1 to 7, wherein in step c) the particles (6) on the at least one subsection (2c) of the squeegee profile (1) impinge at a speed which is sufficiently high that the particles (6) partially penetrate into the microwells (5). 9. The method according to any one of claims 1 to 8, wherein in step d) the at least a portion (2c) of the squeegee profile (1) is heated so that the applied particles (6) substantially retain their shape, or wherein in method step d), the at least one subregion (2c) of the squeegee profile (1) is heated in such a way that the applied particles (6) melt together to form a substantially continuous layer. 10. The method according to any one of claims 1 to 9, wherein in step c) of at least a portion (2c) of the squeegee profile (1) is coated with a thermosetting coating liquid, or wherein in step c) one, in particular thermoplastic, Foil is laminated on at least a portion (2c) of the squeegee profile (1). 11. The method according to any one of claims 1 to 10, wherein in step a) an unvulcanized or at least only partially vulcanized squeegee profile is provided and wherein in step d) the squeegee profile (1) is vulcanized or at least vulcanized. 12. The method according to any one of claims 1 to 11, wherein in step a) the squeegee profile (1) is provided by extrusion. 13. The method according to any one of claims 1 to 12, wherein in step b) the surface structuring of micro-recesses (5) in at least a portion (2c) of the wiper lip portion (2) of the squeegee profile (1), in particular at least in partial areas (2c) the side surfaces of the wiper lip portion (2) of the squeegee profile (1) is introduced, which adjoin the wiping edges (2a) of the wiper blade rubber (10) to be formed. 14. The method according to any one of claims 1 to 13, wherein the squeegee profile (1) is a squeegee double profile whose cross-sectional area corresponds to the cross-sectional area of two squeegees (10), which are connected to each other via the two wiper lip portions (2), in particular the method further comprising the step of: e) separating the squeegee double profile into individual squeegee rubbers (10). 15. squeegee, in particular produced by a method according to one of claims 1 to 14, comprising a squeegee base body (1), wherein at least a portion (2c) of the wiper base body (1) by a plurality of microwells (5) is structured in which the microwells (5) are partially or completely filled with particles (6), in particular overhanging the surface of the at least one subregion (2c) of the squeegee main body (1), or wherein the surface of the at least one subregion (2c) of the Wischgummi basic body (1) is provided with a coating (6) which fills the microwells (5) partially or completely.