CN115536874A

CN115536874A - Wiper rubber with cross-linked matrix and sliding body

Info

Publication number: CN115536874A
Application number: CN202210750175.9A
Authority: CN
Inventors: M·皮伦内特; R·拉伊
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2021-06-30
Filing date: 2022-06-29
Publication date: 2022-12-30
Also published as: DE102021206781A1; FR3124775A1

Abstract

The invention relates to a method for producing a wiping rubber (10), in particular for a window wiper, wherein a first material (11) for a main body (11) of the wiping rubber (10) and a second material (12) for at least one sliding body (12) are co-extruded and/or injected and/or cast to form a main body-sliding body strip (100), wherein the at least one sliding body (12) covers a part of the surface of the main body (11), which part defines a wiping contact for the wiping rubber (10). The first material (11) and the second material (12) each comprise at least one crosslinkable polymer. In order to provide a wiper rubber whose wiping quality can be maintained over a long period of time in a simple, cost-effective and environmentally friendly manner, the second material (12) comprises at least one material-crosslinking agent for crosslinking at least one crosslinkable polymer of the second material (12) with at least one crosslinkable polymer of the first material (11), and/or the first material (11) comprises at least one material-crosslinking agent for crosslinking at least one crosslinkable polymer of the first material (11) with at least one crosslinkable polymer of the second material (12). The invention further relates to a correspondingly produced wiper rubber.

Description

Wiper rubber with cross-linked matrix and sliding body

Technical Field

The invention relates to a method for producing a wiper rubber and to a correspondingly produced wiper rubber.

Background

Wiper rubbers, for example wiper blades for window wipers, are nowadays mostly first extruded as a two-profile strip and then vulcanized. In order to ensure the reduced-friction adhesion of the slip-lacquer coating, the double strips are then usually first halogenated or activated by means of a plasma and then coated with a solvent-containing slip-lacquer by means of a spray application. After curing, for example after drying and/or hardening, the slip-coat layer of the two-profile strip is cut in the middle. Such conventional manufacturing processes therefore comprise at least five process steps (extrusion, vulcanization, halogenation/activation, coating, curing, cutting).

The publication DE 10 2016 213 862 A1 relates to a further method for producing a wiper rubber for a wiper blade of a windshield wiper.

Disclosure of Invention

The invention relates to a method for producing a wiper rubber, in particular for wiper blades, for example for window wipers, for example for vehicles, wherein a first material for a base body of the wiper rubber and a second material for at least one sliding body are coextruded and/or injected and/or cast, in particular extruded, into a base body-sliding body strip. In this case, at least one sliding body covers a part of the surface of the base body, which part defines a wiping contact for wiping rubber.

In this case, the first material and the second material each comprise, in particular, at least one crosslinkable polymer.

In this case, the second material comprises in particular at least one material-crosslinking agent for crosslinking at least one crosslinkable polymer of the second material with at least one crosslinkable polymer of the first material and/or the first material comprises at least one material-crosslinking agent for crosslinking at least one crosslinkable polymer of the first material with at least one crosslinkable polymer of the second material.

In the wiper rubber thus produced, at least one sliding body can advantageously assume the function of a sliding coating. By extruding and/or injecting and/or casting at least one sliding body together with the base body, at least two method steps, namely halogenation/activation and curing, for example drying and/or hardening, of the sliding paint coating can be advantageously saved in comparison with conventional production methods for producing wiper rubbers with sliding paint coatings. In particular, with the aid of this method, at least one sliding body can advantageously be applied, contrary to conventional production methods for producing wiper rubbers with a sliding lacquer coating, directly, i.e., without environmentally harmful halogenation and without solvents, in particular without the use of additional organic solvents, whereby the method can be carried out more easily, more cost-effectively and in particular also more environmentally.

By coextruding and/or injecting and/or casting the first material for the main body and the second material for the at least one sliding body into the main body-sliding body strip, it is already advantageously possible to achieve an improved adhesion between the main body and the at least one sliding body used as a sliding coating, compared to the production method in which the already vulcanized main body is coated with a sliding lacquer coating.

The second material comprises at least one material-crosslinking agent which is designed both for crosslinking at least one crosslinkable polymer of the second material and for crosslinking at least one crosslinkable polymer of the first material, and/or the first material comprises at least one material-crosslinking agent which is designed both for crosslinking at least one crosslinkable polymer of the first material and for crosslinking at least one crosslinkable polymer of the second material, so that the at least one material-crosslinking agent can advantageously form crosslinked chemical bonds, in particular covalent bonds, between the first material and the second material, as a result of which a strong chemical connection can be obtained between the base body and the at least one sliding body, which is substantially stronger than a purely physical attachment, which can advantageously contribute to maintaining the wiping quality of the wiping rubber over a long lifetime.

Overall, the wiper rubber can then be produced in a simple, cost-effective and environmentally friendly manner by this method, the wiper quality of which can be maintained over a long lifetime.

The at least one sliding body can be extruded and/or injected and/or cast, for example in the form of two sliding strips. For example, two sliding strips can be formed at two opposite sides of the base body.

The substrate can for example comprise: at least one wiper lip section, which in particular defines a wiper contact for a wiper rubber; at least one oblique tab section and at least one fastening section. In this case, the at least one sliding body can be formed, for example, on a surface of the wiper lip section, in particular on the tip of the wiper lip section. For example, the at least one sliding body can be formed as two sliding strips at two opposite sides of the wiping lip section, in particular at the tip of the wiping lip section, and/or in particular the at least one wiping edge, in particular the two wiping edges, can be formed at the surface of the wiping lip section, in particular at the tip of the wiping lip section. The at least one sliding body can then advantageously be designed at a functionally important position.

If the base body/slide body/strip is extruded and/or injected and/or cast as a single profile strip, the base body can for example comprise a wiper lip section, an oblique web section and a fastening section.

If the base body/sliding body/strip is extruded and/or injected and/or cast as a two-profile strip, the base body can have, for example, two wiper lip sections, two oblique web sections and two fastening sections. In this case, the two wiper lip sections can in particular be connected to one another on the one hand and to the fastening section on the other hand by means of an oblique web section.

In the context of one embodiment, the first material and the second material comprise a cross-linking agent from the same cross-linking agent-class that cross-links at least one material.

Crosslinker classes are to be understood as meaning, in particular, classes or groups of crosslinkers whose crosslinking is based on the same type of crosslinking mechanism. Examples for crosslinker classes are, for example, the class of peroxide crosslinkers and/or the class of sulfur crosslinkers and/or the class of isocyanate crosslinkers.

The chemical connection between the base body and the at least one sliding body can then advantageously be further optimized.

The first material and the second material can in principle comprise, in particular independently of one another, one polymer or two or three or more polymers, for example one crosslinkable polymer or two or three or more crosslinkable polymers, respectively. For example, the first material and the second material can in particular each comprise independently of one another: especially crosslinkable polymers from one polymer class or mixtures of two or three or more especially crosslinkable polymers from the same or different, especially different polymer classes, for example mixtures of ethylene-propylene-diene terpolymers and natural rubber (Blend) or mixtures of polychloroprene and natural rubber.

Polymer species is to be understood as meaning, in particular, species or groups of polymers which are produced from one and the same monomer or from a plurality of the same monomers. Examples for polymer-classes are, for example, the class of ethylene-propylene-diene terpolymers (EPDM) and/or the class of polychloroprene (CR) and/or the class of polyisoprene and/or the class of Natural Rubber (NR).

In the context of another embodiment, the first material and the second material comprise at least one crosslinkable polymer from the same polymer-class. The chemical connection between the base body and the at least one sliding body can then advantageously be further optimized.

Within the scope of another embodiment, the first material and the second material each comprise at least a peroxide-crosslinkable polymer and at least one peroxide-crosslinking agent. The chemical bond between the base body and the at least one sliding body can then advantageously be further optimized in the case of peroxidically crosslinkable polymers, such as ethylene-propylene-diene terpolymers (EPDM).

Within the scope of another alternative or additional embodiment, the first material and the second material comprise at least one sulfur-crosslinkable polymer and at least one sulfur crosslinking agent, respectively. The chemical connection between the base body and the at least one sliding body can then advantageously be further optimized in the case of polymers which can be crosslinked by sulfur, such as polychloroprene (CR) and/or polyisoprene and/or Natural Rubber (NR).

The crosslinker can comprise, inter alia, at least one crosslinker component. If desired, the crosslinker can comprise two or more, if desired even three or four or more crosslinker components.

The peroxide-crosslinking agent can include, inter alia, at least one peroxide. For example, the at least one peroxide can comprise or be dicumyl peroxide [ CAS 80-43-3] and/or bis- (2-tert-butyl-peroxyisopropyl) -benzene [ CAS 25155-25-3] and/or tert-butylcumyl peroxide [ CAS 3457-61-2] and/or 2, 5-dimethyl-2, 5-di (tert-butylperoxy) -hexane [78-63-7] and/or di-tert-butyl peroxide [110-05-4] and/or 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexyne-3, [ CAS 1068-27-5] and/or butyl-4, 4-di- (tert-butylperoxy) -valerate [ CAS 995-33-5] and/or 1, di- (tert-butylperoxy) -3, 5-trimethylcyclohexane [ CAS 6731-36-8] and/or tert-butylperoxybenzoate [ CAS 614-45-9].

The sulfur crosslinking agent can include, inter alia, at least one sulfur donor. For example, the at least one sulfur donor can comprise or be caprolactam disulfide and/or elemental sulfur. Furthermore, the sulfur crosslinking agent can, for example, include at least one accelerator. The at least one accelerator can for example comprise or be a dithiocarbamate and/or a thiuram and/or a thiazole and/or a thiazolidine, such as 3-methylthiazolidine-thione-2 [ CAS 1908-87-8], and/or a thiazolesulfonamide and/or bird 30623. Furthermore, the sulfur crosslinking agent can be given, inter alia, an activator, such as zinc oxide.

In the context of another embodiment, the cross-linking agent cross-linking the at least one material of the first material and the cross-linking agent cross-linking the at least one material of the second material comprise at least one identical cross-linking agent component. The chemical connection between the base body and the at least one sliding body can then advantageously be further optimized.

In the context of another embodiment, the crosslinking agent for crosslinking at least one material of the first material and the crosslinking agent for crosslinking at least one material of the second material comprise at least one identical peroxide and/or at least one identical sulfur donor and/or at least one identical accelerator. The chemical connection between the base body and the at least one sliding body can then advantageously be further optimized.

In the context of another embodiment, the second material is more strongly cross-linked than the first material. The wiping quality of the wiping rubber can then advantageously be optimized. The base body can in particular be equipped with a high elasticity for the wiping movement. In this case, the at least one sliding body can have a high rigidity, in particular, in order to provide a wiping function and a sliding function.

In the context of a further embodiment, the second material comprises a higher proportion of crosslinkable functional groups than the first material, for example double bonds and/or a higher concentration of at least one crosslinker component, in particular a higher peroxide concentration and/or a higher accelerator concentration and/or a higher sulfur donor concentration. It is then possible to obtain a more vigorous crosslinking and thus a higher hardness of the second material and a lower crosslinking and thus a higher elasticity of the first material, in particular also in the case of using crosslinkable polymers from the same polymer class in the first and second materials, for example using ethylene-propylene-diene terpolymers (EPDM) in the first and second materials or polychloroprene (CR) in the first and second materials or polyisoprene, in particular Natural Rubber (NR), in the first and second materials.

Within the scope of another embodiment, the first material and the second material each comprise at least one peroxide-crosslinkable polymer from the class of ethylene-propylene-diene terpolymers and at least one peroxide-crosslinking agent. In this case, the second material can comprise, in particular, a higher proportion of crosslinkable functional groups than the first material, for example double bonds, for example a higher proportion of dienes of an ethylene-propylene-diene terpolymer, and/or a particularly higher proportion of compounds having at least one additional double bond, for example polybutadiene and/or polyisoprene and/or ethylene glycol dimethacrylate, and/or a higher peroxide concentration. A more vigorous crosslinking and therefore a higher hardness of the second material and a lower crosslinking and therefore a higher elasticity of the first material can then advantageously be achieved.

For example, the first material can comprise from ≥ 90% by weight to ≤ 95% by weight of the ethylene-propylene-diene terpolymer, from ≥ 3% by weight to ≤ 5% by weight of a compound having at least one additional double bond, such as polybutadiene and/or polyisoprene and/or ethylene glycol-dimethacrylate, and from ≥ 1% by weight to ≤ 5% by weight of the peroxide. The second material can, for example, comprise from 65% by weight to 85% by weight of ethylene-propylene-diene terpolymer, from 10% by weight to 20% by weight of a compound having at least one additional double bond, for example polybutadiene and/or polyisoprene and/or ethylene glycol dimethacrylate, and from 5% by weight to 15% by weight of peroxide, based on the total polymer mass.

In the context of another alternative or additional embodiment, the first material and the second material each comprise at least one sulfur-crosslinkable polymer from the class of polychloroprene and at least one sulfur crosslinking agent. In this case, the second material can comprise a higher promoter concentration than the first material. A more severe crosslinking and therefore a higher hardness of the second material and a lower crosslinking and therefore a higher elasticity of the first material can thus advantageously be achieved.

Within the scope of another alternative or additional embodiment, the first material and the second material respectively comprise at least a sulfur-crosslinkable polymer from the class of polyisoprenes and/or natural rubbers and at least one sulfur crosslinking agent. In this case, the second material can in particular comprise a higher sulfur donor concentration and/or a higher promoter concentration than the first material. A more vigorous crosslinking and therefore a higher hardness of the second material and a lower crosslinking and therefore a higher elasticity of the first material can then advantageously be achieved.

In the context of a further embodiment, the second material is pasty. The pasty form has the following advantages: in a solid lubricant comprising a second material, much less grinding is possible than in the case of use in suspended form. An improvement in the wiping quality of the wiper rubber and in the wear resistance of the sliding body and thus in the service life of the wiper rubber can be achieved by a smaller grinding.

In the context of a further embodiment, the second material furthermore comprises at least one solid lubricant, in particular graphite and/or Polytetrafluoroethylene (PTFE) and/or Polyethylene (PE) and/or molybdenum sulfide (MoS 2). The method can be particularly advantageously suitable for incorporating the solid lubricant into the sliding body layer, since it is thereby possible to avoid the polymer and the solid lubricant being suspended or dispersed in a solvent, which expands the choice and number of polymers that can be used.

In the context of a further embodiment, the matrix/slide bar is cured, for example, in a salt bath or in a hot air continuous furnace, in particular in the case of the formation of a cross-linked chemical bond between the first material and the second material. In this case, the first material can be vulcanized in particular and the second material can be hardened. By jointly curing the first and second material, at least one method step, for example curing the sliding paint layer, can advantageously be dispensed with.

In the context of a further embodiment, the cured base body/sliding body/strip is cut at least once, in particular transversely to the strip direction, when the wiper rubber is formed. In the case of a design of the base body/slide body/strip in the form of a single profile strip, a cut of each wiper rubber can be sufficient here, in particular transversely to the strip direction. If the base body/slider strip is designed in the form of a double profile strip, the double profile strip can be cut into, in particular, two wiper rubbers, in particular by an axial cut, in particular between two wiper lip sections, and by a cut transverse to the strip direction.

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

The invention further relates to a wiper rubber, in particular for a wiper blade, for example for a window wiper, for example for a vehicle, which is produced by the method according to the invention.

The wiper rubber produced according to the invention can be verified by means of additional EDX analysis, for example, by means of an optical microscopic recording in cross section and an electron microscopic recording in cross section.

Further features and advantages of the wiper rubber according to the invention are apparent from the explanations in conjunction with the method according to the invention and from the drawings and the description of the drawings.

Drawings

Further advantages and advantageous embodiments of the subject matter according to the invention are shown in the figures and are explained in the following description. It should be noted here that the drawings have only descriptive features and are not intended to limit the invention in any way. Wherein:

fig. 1 shows a schematic cross section for illustrating an embodiment of the manufacturing method according to the invention; and is provided with

Fig. 2a, b show schematic cross sections of an extrusion die for carrying out the embodiment shown in fig. 1.

Detailed Description

Fig. 1 shows that, in the illustrated embodiment of the method according to the invention for producing a wiper rubber 10, in particular for a window wiper, a first material 11 for a main body 11 of the wiper rubber 10 and a second material 12 for at least one sliding body 12 are co-extruded and/or injected and/or cast into a main body-sliding body strip 100 in the form of a double profile strip. The base body 11 has two wiper lip sections a, a ', two inclined web sections B, B' and two fastening sections C, C ', wherein the two wiper lip sections a, a' are connected to one another on the one hand and to the fastening sections C, C 'by the inclined web sections B, B', respectively, on the other hand. In this case, at least one sliding body 12 covers a part of the surface of the base body 11, which is intended for the wiping contact of the wiping rubber 10. In particular, at least one slide body 12 is formed here as two slide strips at two opposite sides at the surface of the wiper lip sections a, a' of the main body 11. It is then advantageously possible to configure at least one slide body 12 at a functionally important position.

In this case, the first material 11 and the second material 12 each comprise at least one crosslinkable polymer. In this case, the second material 12 may in particular comprise at least one cross-linking agent for cross-linking the material, which cross-linking agent is designed both for cross-linking at least one cross-linkable polymer of the second material 12 and for cross-linking at least one cross-linkable polymer of the first material 11. As an alternative or in addition thereto, the first material 11 can comprise at least one material-crosslinking agent which is designed not only for crosslinking at least one crosslinkable polymer of the first material 11 but also for crosslinking at least one crosslinkable polymer of the second material 12. In particular, the first material 11 and the second material 12 can comprise a cross-linking agent from the same cross-linking agent species, which cross-links at least one material. For example, the crosslinking agent that crosslinks the at least one material of the first material 11 and the crosslinking agent that crosslinks the at least one material of the second material 12 can comprise at least one identical crosslinking agent component, such as at least one identical peroxide and/or at least one identical sulfur donor and/or at least one identical accelerator. Furthermore, the first material 11 and the second material 12 can also comprise at least one crosslinkable polymer from the same polymer-species.

The second material 12 is capable of being crosslinked more strongly than the first material 11 and comprises at least one solid lubricant, such as graphite, polytetrafluoroethylene, polyethylene and/or molybdenum sulphide.

For example, the first material 11 and the second material 12 can comprise at least a peroxide-crosslinkable polymer, for example from the class of ethylene-propylene-diene terpolymers, and at least one peroxide-crosslinking agent, respectively. In order to obtain a more severe crosslinking of the second material 12, the second material 12 can comprise a higher proportion of crosslinkable functional groups, in particular double bonds, and/or a higher concentration of at least one crosslinking agent component, in particular a higher peroxide concentration, than the first material 11.

In other embodiments, the first material 11 and the second material 12 can comprise at least one polymer capable of sulfur crosslinking, in particular natural rubber, for example from the class of polychloroprene and/or from the class of polyisoprene, respectively, and at least one sulfur crosslinking agent. In order to obtain a more vigorous crosslinking of the second material 12, the second material 12 can comprise a higher concentration of at least one crosslinking agent component, in particular a higher promoter concentration and/or a higher sulfur donor concentration, than the first material 11.

The matrix/slide bar 100 shown in fig. 1 can be cured (not shown), for example, in a salt bath or in a hot air continuous furnace, in particular, in the formation of cross-linked chemical bonds between the first material 11 and the second material 12. The cured base-slide bar 100 can then be divided, for example, directly after curing, for example, in a salt bath, in the axial direction and also transversely to the bar direction, for example, into wiper rubbers 10 (not shown).

Fig. 2a and 2b show an embodiment of an extrusion die W in the form of an extrusion tip nozzle for carrying out the embodiment shown in fig. 1 of the manufacturing method according to the invention. Fig. 2a shows a cross section of a first nozzle section of the extrusion tip nozzle W in which the substrate is shaped. Fig. 2b shows a further cross section of a second nozzle section of the extrusion tip nozzle W, in which at least one sliding body is coextruded and/or coinjected and/or co-cast onto the base body. The second nozzle section can follow the first nozzle section in particular directly, for example without a gap.

Claims

1. Method for producing a wiper rubber (10), in particular for a window wiper, wherein a first material (11) for a main body (11) of the wiper rubber (10) and a second material (12) for at least one sliding body (12) are coextruded and/or injected and/or cast to form a main body-sliding body strip (100), wherein the at least one sliding body (12) covers a part of the surface of the main body (11) which is intended to form a wiper contact for the wiper rubber (10),

wherein the first material (11) and the second material (12) each comprise at least one crosslinkable polymer,

wherein the second material (12) comprises at least one material cross-linking agent for cross-linking at least one cross-linkable polymer of the second material (12) with at least one cross-linkable polymer of the first material (11) and/or

Wherein the first material (11) comprises at least one material cross-linking agent for cross-linking at least one cross-linkable polymer of the first material (11) with at least one cross-linkable polymer of the second material (12).

2. Method according to claim 1, wherein the first material (11) and the second material (12) comprise a cross-linking agent from the same cross-linking agent-species, cross-linking of at least one material.

3. Method according to claim 1 or 2, wherein the first material (11) and the second material (12) comprise at least one crosslinkable polymer from the same polymer-species.

4. The method of any one of claims 1 to 3,

wherein the first material (11) and the second material (12) comprise at least one peroxide-crosslinkable polymer and at least one peroxide-crosslinking agent, respectively, and/or

Wherein the first material (11) and the second material (12) comprise at least one polymer capable of sulphur cross-linking and at least one sulphur cross-linking agent, respectively.

5. Method according to any of claims 1 to 4, wherein the cross-linking agent of at least one material cross-linking of the first material (11) and the cross-linking agent of at least one material cross-linking of the second material (12) comprise at least one same cross-linking agent component.

6. Method according to any of claims 1 to 5, wherein the cross-linking agent of at least one material cross-linking of the first material (11) and the cross-linking agent of at least one material cross-linking of the second material (11) comprise at least one identical peroxide and/or at least one identical sulfur donor and/or at least one identical accelerator.

7. Method according to any of claims 1 to 6, wherein the second material (12) is more strongly cross-linked than the first material (11).

8. Method according to any one of claims 1 to 7, wherein the second material (12) comprises a higher share of crosslinkable functional groups, in particular double bonds, than the first material (11), and/or comprises a higher concentration of at least one crosslinker component, in particular a higher peroxide-concentration and/or a higher accelerator-concentration and/or a higher sulphur-donor-concentration.

9. The method of any one of claims 1 to 8,

wherein the first material (11) and the second material (12) each comprise at least a peroxide-crosslinkable polymer from the class of ethylene-propylene-diene terpolymers and at least one peroxide-crosslinking agent, wherein the second material (12) comprises a higher share of crosslinkable functional groups, in particular double bonds, than the first material (11), in particular a higher share of dienes of the ethylene-propylene-diene terpolymer, and/or a higher share of at least one compound having additional double bonds, and/or a higher peroxide-concentration, and/or

Wherein the first material (11) and the second material (12) comprise at least one sulfur-crosslinkable polymer from the class of polychloroprene and at least one sulfur crosslinking agent, respectively, wherein the second material (12) comprises a higher promoter-concentration than the first material (11) and/or

Wherein the first material (11) and the second material (12) respectively comprise at least a sulfur-crosslinkable polymer from the class of polyisoprene and/or natural rubber and at least one sulfur crosslinking agent, wherein the second material (12) comprises a higher sulfur-donor-concentration and/or a higher accelerator-concentration than the first material (11).

10. Method according to any one of claims 1 to 9, wherein the second material (12) is pasty.

11. Method according to any one of claims 1 to 10, wherein the second material (12) furthermore comprises at least one solid lubricant, in particular graphite and/or polytetrafluoroethylene and/or polyethylene and/or molybdenum sulphide.

12. The method according to one of claims 1 to 11, wherein the matrix-slide-strip (100) is cured, in particular in a salt bath or in a hot air continuous furnace, in particular in the case of the formation of a cross-linked chemical bond between the first material (11) and the second material (12).

13. Method according to one of claims 1 to 12, wherein the cured matrix/slide strip (100) is cut at least once, in particular transversely to the strip direction, with the wiper rubber (10) being formed, in particular wherein the matrix/slide strip (100) is formed in the form of a double profile and the double profile strip is cut axially and transversely to the strip direction into the wiper rubber.

14. Wiper rubber (10), in particular for wiper blades, in particular for window wipers, in particular for vehicles, produced by a method according to one of claims 1 to 13.