Process for producing a sealing semi-finished product, sealing semi-finished product and use

Abstract

The invention relates to a method for producing a sealing semi-finished product, in which a profile strip (100) is produced by extruding (210) an elastomer, a sliding coating (110) with a predeterminable layer thickness is applied (230) as evenly as possible to a surface of the profile strip (100), and the sliding coating (110) is subsequently cured (270), wherein a reflective or luminescent sliding coating (110) is used. The invention further relates to a sealing semi-finished product and a use thereof.

Description

[0001] The invention relates to a method for producing a sealing semi-finished product according to the preamble of claim 1, a sealing semi-finished product according to claim 4 and a use thereof according to claim 5.

[0002] The optimization of modern vehicles with regard to the reduction and / or insulation of drive noise, tire noise, and wind noise leads to a greater perception of contact point noise among users. This means noise caused by oscillating relative movements of components in physical contact, which was previously lost in the general background noise. Such component pairings include, for example, those between fixed and moving body parts, such as vehicle doors, sunroofs, and so on. Typically, at least one component in such a pairing is equipped with an elastic seal designed to prevent water and wind penetration and simultaneously prevent noise from entering the passenger compartment.At the sealing point, i.e., the contact point between the sealing element and other body parts, contact point noises arise primarily due to the so-called stick-slip effect (from the English "stick" and "slip" "slide"), also known as the adhesive-slip effect or (self-excited) friction vibration, which describes the jerky sliding of solid bodies moving against each other. Common examples are creaking doors, rattling windshield wipers, and a wet fingertip rubbing against a latex balloon or the rim of a drinking glass. Common countermeasures include reducing the difference between sliding and static friction, often by reducing the overall friction, for example, through lubrication or the application of a lubricating coating.However, in order to effectively prevent noise, it is of great importance that the anti-friction coating forms a closed layer, because there is a proven connection between a defective coating (no closed paint film, nests with no coating) and the resulting disturbing noise.

[0003] DE 199 45 848 A1 describes aqueous polyurethane coating dispersions suitable for coating elastomers to achieve a surface with a very low coefficient of friction. Elastomer parts coated in this way are suitable for sealing window shafts, for movable glass parts, and / or as sealing profiles in vehicle construction, preferably in automotive engineering.

[0004] EP 3 290 194 A1 discloses a method for producing a weatherstrip for a car, comprising a sealing part with a U-shaped cross section and a sealing function, a coupling element formed integrally with the sealing part so as to be connectable to a flange portion of a car, and a suture material inserted into the coupling element, the method comprising: (a) a weatherstrip manufacturing step in which the suture material and a thermoplastic elastomer are extruded and molded; (b) a pretreatment step in which the surface of the manufactured weatherstrip is pretreated; (c) a lubricant application step in which a lubricant prepared by mixing silicone and polyurethane is applied to the surface of the weatherstrip pretreated by the pretreatment step;and (d) a curing step of curing the lubricant coating layer formed by the lubricant application step. This can improve the emotional quality, compression set performance, reinforcement, and durability of the automotive weatherstrips.

[0005] A vehicle weather seal proposed in WO 2005 / 021308 A1 includes a reflective surface to improve visibility to other road users. The reflective surface may be disposed on a dynamic seal, a static seal, or a trim part of the weather seal. The reflective surface may be extruded, molded, particulate, flocked, or a colliquitous powder coating. The reflective surface may comprise a reflective matrix, reflective articles, or a reflective textile or fabric. The reflective surface may be incorporated into or used with a friction-reducing material to create a friction-reducing reflective dynamic seal.

[0006] DE 10 2008 055 025 A1 discloses a strand-shaped sealing profile made of elastic or elastomeric material, in particular for sealing a pane of glass against a frame of a door or window, which comprises: a base body which is intended to bear against the frame, a sealing section which is connected to the base body and is intended to bear against the pane and to extend away from the frame and away from the peripheral edge of the pane, and a lip section which is connected to the base body and has a free end which is intended to bear against the pane and to extend away from the frame to the peripheral edge of the pane and has a multiplicity of, in particular regularly arranged, notches over substantially the entire length of the strand, which run from the free end transversely to the longitudinal extent of the strand and only partially penetrate the lip section with regard to its thickness, so that a material web with a defined thickness remains.At least the lip section is provided with a heat-reflecting coating. The heat-reflecting coating is usually a surface coating and is preferably transparent. It can be color-coordinated, for example, with the material of the lip section, or it can also be optically reflective.

[0007] Growing design requirements for haptics and appearance, such as tight gaps, complicate noise-optimized design. Likewise, as customer customization options increase, so does the number of possible combinations of material pairings. Complaints due to contact point noise are increasing, and these must be addressed on a vehicle-by-vehicle basis. This leads to unwanted visits to the workshop and high costs.

[0008] An object of the invention is therefore to improve sealing elements, in particular for use in vehicle construction, in such a way that contact point noises are avoided as far as possible.

[0009] The object is achieved according to the invention by a method having the features of the characterizing part of claim 1 and by a sealing semi-finished product having the features of claim 4 and a use having the features of claim 5.

[0010] Advantageous embodiments of the invention are the subject of the subclaims.

[0011] In a method for producing a sealing semi-finished product, in which a profile strip is produced by extruding an elastomer, a sliding coating with a predeterminable layer thickness is applied as evenly as possible to a surface of the profile strip, and the sliding coating is then cured, the invention proposes that a reflective or luminescent sliding coating is used, wherein during the application of the sliding coating to the surface of the profile strip, an optical control of the uniformity and / or the layer thickness of the sliding coating is carried out with the aid of software by means of digital image processing, wherein fluctuations in the layer thickness and / or defects in the sliding coating are determined and recorded from the intensity of the light reflected or emitted by the surface, and the determined fluctuations in the layer thickness and / or defects in the sliding coating are marked on the surface of the profile strip,where marking is carried out by mechanically introducing at least one disturbance in the anti-friction coating that is visible to the naked eye or by at least one local increase in the layer thickness of the anti-friction coating.

[0012] A semi-finished sealing product is defined below as intermediate products that cannot yet be used directly as a sealing element on their own, but are, for example, manufactured in a virtually continuous form and delivered on a roll to customers who then manufacture a sealing element from a section of the semi-finished sealing product and install it, for example, in a vehicle. Such semi-finished sealing products typically comprise a profile strip, usually produced by extrusion from an elastomer material. This is often subsequently further treated, for example, by flocking and / or applying a lubricating coating and / or applying a double-sided adhesive tape.

[0013] By applying a reflective or luminescent anti-friction coating, it becomes possible to either detect quality problems during the production of the semi-finished seal and, if necessary, address them. For example, to mark or repair identified defects such as variations in layer thickness or defects in the anti-friction coating, or to inspect the semi-finished seal for defects and address these defects only during further use, for example in the production of sealing elements. In the first variant, the manufacturer of the semi-finished seal can improve the quality of its product by marking and / or repairing potential defects. In the second case, the vehicle manufacturer can prevent the used section from being defective when using the semi-finished seal by inspecting the section for such defects before separating it from the semi-finished seal.

[0014] A basic idea of ​​the invention is to use a reflective or luminescent anti-friction coating, i.e. a anti-friction coating that can emit light, to make defective areas of the anti-friction coating visible as part of quality assurance.

[0015] For example, it may be provided that a conventional lubricating varnish is used, to which, however, according to the invention, a reflective or luminescent substance or reflective or luminescent particles are added before application.

[0016] The anti-friction coating can be applied to a surface of the profile strip during the manufacturing process of the sealing semi-finished product, for example immediately after extrusion, or after the extrudate has cured, and then cured, for example by exposure to heat or UV light.

[0017] To detect defects, the invention provides for a visual inspection of the uniformity and / or thickness of the anti-friction coating to be carried out during the application of the anti-friction coating to the surface of the profile strip. Such a visual inspection can be performed inline, i.e., during the ongoing manufacturing process, because available optical inspection methods are fast enough for this.

[0018] The invention further provides for an optical inspection to be carried out using software-supported digital image processing, whereby fluctuations in the coating thickness and / or defects in the anti-friction coating are determined and recorded based on the intensity of the light reflected or emitted by the surface. For this purpose, for example, a digital camera can be arranged such that the coated surface of the profile strip is continuously moved past the camera, and the camera continuously captures images of the surface and forwards them to a data processing device on which image processing software is running.

[0019] With a reflective anti-friction coating, it is advisable to arrange a lighting device in such a way that uniform, consistent, and defined illumination of the surface of the profile strip is ensured. If this uniform light is then reflected unevenly by the surface of the profile strip, this can indicate an uneven, i.e., defective, coating. With a luminescent anti-friction coating, the anti-friction coating itself represents the light source, and fluctuating brightness also indicates a defective coating.

[0020] The image processing software then detects brightness fluctuations on the coated surface in the images captured by the camera, which are due to fluctuations in the film thickness of the anti-friction coating. By previously training the software or by pre-programming a relationship between brightness and film thickness, defects can be identified. For example, the software can store a lookup table with pairs of values ​​for brightness and film thickness. Furthermore, the software can be able to determine the film thickness based on the brightness using a machine learning algorithm.

[0021] If a defect is detected, fluctuations in the layer thickness and / or defects in the anti-friction coating on the surface of the profile strip are marked according to the invention.

[0022] According to the invention, marking is carried out by mechanically introducing at least one defect in the anti-friction coating that is visible to the naked eye, for example selective local damage to or removal of the anti-friction coating; alternatively or additionally, the invention provides for marking to be carried out by at least one local increase in the layer thickness of the anti-friction coating. A further possibility is for marking to be carried out by affixing at least one label to the not yet cured anti-friction coating. Since the visual inspection of the layer quality takes place downstream of the application of the anti-friction coating, a defective area can, for example, be provided with markings on both sides so that precisely this area can be excluded from further use.For example, a marking can be designed in such a way that it also indicates on which side of the marking the defective area is located, in which the anti-friction coating is not OK, and on which side of the marking the anti-friction coating is OK, so that this area can continue to be used.

[0023] The object of the invention is also achieved by a semi-finished sealing product and a sealing element produced from a semi-finished sealing product, which was produced using a method according to the invention. Due to its coating with a reflective or luminescent anti-friction coating, the semi-finished sealing product according to the invention makes it possible to detect defects either immediately after the production of the semi-finished sealing product, for example, by a manufacturer of the semi-finished sealing product, or / and at a later time, for example, during further processing of the semi-finished sealing product into a sealing element, for example, by a vehicle manufacturer, and to either mark the affected areas or / and avoid their use in the production of sealing elements.In addition, a previously common procedure in which defective areas of a sealing semi-finished product, for example mechanical damage to the profile strip due to faulty extrusion, were separately marked with a colored lacquer can be replaced by the optical inspection of the reflective or luminescent anti-friction lacquer.

[0024] Furthermore, the object is achieved according to the invention by using a sealing semi-finished product of the type described, in which a section is severed from the sealing semi-finished product, and a sealing element is produced from the severed section of the sealing semi-finished product. According to the invention, a visual inspection of the uniformity and / or the layer thickness of the anti-friction coating can be carried out before the section is severed. This visual inspection can be carried out alternatively or in addition to the visual inspection at the manufacturer of the sealing semi-finished product, which was described in detail above, for example at a user of the sealing semi-finished product, such as a vehicle manufacturer, when the sealing semi-finished product is manufactured into sealing elements.This alternative or additional optical control can be designed analogously to that already described above for the manufacturing process, and it can be used in an analogous manner after a decision as to whether the layer of the anti-friction coating is OK, to mark defect areas and to avoid the use of defective sections of the sealing semi-finished product.

[0025] Embodiments of the invention are explained in more detail below with reference to drawings.

[0026] Showing: Fig. 1 schematically shows a sealing semi-finished product according to the invention, and Fig. 2 schematically shows a flow diagram of an embodiment of a method according to the invention.

[0027] Corresponding parts are provided with the same reference numerals in the figures.

[0028] Fig. Figure 1 shows a section of a profile strip 100 of a sealing semi-finished product, of which a surface area is additionally shown enlarged. The enlarged area relates to a transition area between an area on the right side of the illustration, in which the anti-friction coating 110 forms a continuous layer, and an area on the left side of the illustration, in which the anti-friction coating 110 is interrupted by defects 120. The area with the defects 120 is defective because it would lead to contact point noise, and must therefore be rejected.

[0029] An embodiment of the manufacturing method according to the invention, which enables the detection and separation of defective areas, is shown in Fig. 2 shown.

[0030] The process begins at start 200. First, a profile strip 100 is produced by extrusion 210 of an elastomer material, which then undergoes a curing step 220. This is followed by painting 230 of a surface of the profile strip 100 with a reflective or luminescent anti-friction coating 110. This coating is then subjected to an optical inspection 240, which includes image capture and subsequent image processing, after which a decision 250 is made as to whether the coating is OK, i.e., acceptable, or NOK, i.e., not acceptable.

[0031] If the coating is not satisfactory (not OK), a marking step 260 of the defective area follows. Otherwise, the curing step 270 of the anti-friction coating 110 follows directly. The process ends at step 280.

Claims

[1] Method for producing a sealing semi-finished product, in which a profile strip (100) is produced by extruding (210) an elastomer, a sliding coating (110) with a predeterminable layer thickness is applied as evenly as possible to a surface of the profile strip (100) (230) and then the sliding coating (110) is cured (270), characterized bythat a reflective or luminescent anti-friction varnish (110) is used, wherein during the application of the anti-friction varnish (110) to the surface of the profile strip (100), an optical check (240) of the uniformity and / or the layer thickness of the anti-friction varnish (110) is carried out with the aid of software by means of digital image processing, wherein fluctuations in the layer thickness and / or defects (120) of the anti-friction varnish (110) are determined and recorded from the intensity of the light reflected or emitted by the surface, and determined fluctuations in the layer thickness and / or defects (120) of the anti-friction varnish (110) are marked (260) on the surface of the profile strip (100), wherein a marking (260) is carried out by mechanically introducing at least one disturbance in the anti-friction varnish (110) that is visible to the naked eye or by at least one local increase in the layer thickness of the anti-friction varnish (110). [2] Method according to claim 1, characterized bythat a lubricating varnish (110) is used to which a reflective or luminescent substance or reflective or luminescent particles have been added before application. [3] Method according to claim 1 or 2, characterized by that marking (260) is carried out by sticking at least one label onto the not yet cured lubricating varnish (110). [4] Sealing semi-finished product, produced by a process according to one of claims 1 to 3. [5] Use of a sealing semi-finished product according to claim 4, in which a section is separated from the sealing semi-finished product and a sealing element is produced from the separated section of the sealing semi-finished product, wherein an optical inspection (240) of the uniformity and / or the layer thickness of the anti-friction varnish (110) is carried out before the section is separated.

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