Method of producing a media seal material composite, metal sleeve and sensor

Abstract

The invention relates to a method for producing a media-sealing material composite having a metal sleeve and an electrically insulating plastic at least partially surrounding the metal sleeve, wherein the surface of the component which the plastic contacts is pretreated in order to promote the adhesion of the plastic to the component, wherein the pretreatment is a mechanical and / or chemical and / or physical pretreatment, characterized in that the coated metal sleeve is completely surrounded by a metal surface having photocatalytic properties, the surface is treated photocatalytically over the entire area on the outside and inside of the metal sleeve, and the coated metal sleeve of the preassembled interface is activated by means of UV irradiation. Finally, the invention also relates to a plug connector or a sensor comprising a metal sleeve.

Description

TECHNICAL FIELD

[0001] The invention relates to a method for producing a media material composite, in particular a media-tight arrangement of a solid body surrounded by plastic, which is preferably a shielded electrical plug connector. Furthermore, the invention relates to a preferably cylindrical metal sleeve, which is used in particular as a component of a plug connector. Finally, the invention relates to a plug connector or sensor comprising a metal sleeve. BACKGROUND

[0002] It should be noted here that the solid body or the metal component can be surrounded by plastic by means of different methods. The injection-molding process is mentioned below only by way of example and is not limited thereto.

[0003] In particular, many applications can use encapsulated plugs, sensor areas and / or outdoor areas being referred to only by way of example. Depending on the specific field of application, there are high requirements for the tightness of such plugs. This is referred to as the need for media-tight encapsulation. Depending on the protection class, in particular IP67, IP68 or IP69K, the encapsulation can be the last operation before the finished product. In the event of a leak, all previous added value becomes worthless, for example, the encapsulated plug becomes a reject. In the case of external applications (outdoor plug, HEC), the tightness is even more important, and the requirements for the materials and / or material composites increase. This can require an increase in the tightness, for example, the protection classes IPX7, IPX8 or IPX9K, so that the media-tight material composite is sufficiently protected even in the case of high-pressure / steam-jet cleaning. Furthermore, the requirements for maximum weather resistance can increase, for example, the requirements for resistance to UV radiation and / or scatter.

[0004] It is known from practice that media-tight encapsulation can be achieved very well for freshly molded components. However, if the components age, gaps can form due to, for example, the shrinkage of the boundary layer between the metal sleeve and the encapsulation. Due to the hygroscopic effect, moisture penetrates the component through the gaps.

[0005] In addition to the aging process, the different expansion coefficients of the metal and the encapsulation material, which is usually made of plastic, are also a cause of cracks. Further important influencing criteria are the materials or combinations thereof, the geometry of the component, the production method, the tool design and the corresponding process management. Material factors for the failure of the media-tight material composite are the formation of gaps and the occurrence of microcracks in the plastic component, which can essentially be attributed to a lack of adhesion between the metal component and the plastic component, but also to mechanical solidification stresses. SUMMARY

[0006] It is therefore an object of the present invention to propose a method according to which the region surrounded by plastic is also media-tight over a long period of time.

[0007] In particular, this will apply to the interface between a usual metal part and a plastic, in particular as a component of a plug connector. Preferably, a crack- and gap-free encapsulation and an improved adhesion of the metal-plastic composite will be achieved. Finally, a corresponding interface will be presented, which has a metal sleeve surrounded by plastic, which is produced by the method according to the invention.

[0008] The method according to the invention achieves the object by means of the features of the invention. Thus, a medium-tight plastic coating is produced around a solid body, in particular around a component of a shielded electrical plug, which can be, for example, a component of a sensor. According to the invention, the surface of the component in contact with the plastic is pretreated in order to increase the adhesion of the plastic to the component.

[0009] The invention is based on the idea of establishing a wetting improvement between a metal component and a plastic during the manufacturing process, which is due to an optimization of the interfacial energy with respect to the surface energy or the surface tension of the respective components. Ultimately, this involves an optimization of the contact angle during wetting.

[0010] Due to the sufficiently good adhesion, the formation of a gap between the metal surface and the plastic is effectively reduced / avoided, even in the case of a longer-term use, even in the case of components having different expansion coefficients. This is advantageous for the product, since the medium-tight material composite becomes more robust. As a result, a sufficient tightness can also be ensured under adverse conditions.

[0011] According to one embodiment, the solid body is encapsulated by plastic, for example by polyurethane. The encapsulation takes place after the pretreatment, in particular directly after the pretreatment. Since the result of the encapsulation strongly depends on the adhesion / cleanliness of the plastic on the solid body, a short time period between the pretreatment and the encapsulation is advantageous.

[0012] The solid body can generally be a plug-in part. It can also be, for example, a housing or a solder layer around a plug connector, which is preferably produced by means of integrated metal-plastic injection molding "IMPIM". The encapsulation of such a structure can also be significantly improved by the pretreatment.

[0013] The effect of the pretreatment can also be improved by maximizing the interlocking of the plug sleeve and the plastic encapsulation part. For this purpose, for example, sandblasting, laser structuring, in particular nanoscale engraving, are presented.

[0014] As an alternative to the encapsulation, the solid body can also be cast (poured) with plastic or sintered in plastic. As a result of the pretreatment, the adhesion can also be optimized here and the formation of gaps and / or cracks can be reduced.

[0015] Advantageously, the solid body is a sleeve, or an arrangement including a sleeve, wherein the sleeve may be cylindrical. Therefore, the plug includes a plug sleeve. The plug sleeve may be in direct contact with the plastic at least partially via a contact area, wherein this contact area may be pre-treated.

[0016] The pretreatment of the plug sleeve can be mechanical and / or chemical and / or physical pretreatment. It may be important here that the pretreatment process facilitates adhesion between the metal and the plastic material.

[0017] When geometric optimization or similar structural measures are already included, such as setting one or more circumferential grooves as a labyrinth for the medium, pretreatment will also result in a significant improvement in sealing, preventing media penetration. Pretreatment combined with another geometry or additional component can also achieve significant improvements. For example, shrink tubing applied to the solid metal body before encapsulation, or O-rings introduced into the grooves of the solid metal body before encapsulation, are mentioned.

[0018] Pretreatment replaces various processes related to optimizing wetting, particularly those involving commonly used adhesion promoters / initiators specifically suited to the encapsulation materials used, especially polyurethane as an encapsulation material.

[0019] Within the scope of process optimization, additional variations of pretreatment can be performed, for example, in the form of a solid metal body coated with titanium dioxide before packaging.

[0020] The pretreatment is based on a photocatalytic method and can be performed by ultraviolet irradiation, including surface cleaning and water layer formation due to photocatalytic self-cleaning. In this way, the surface can be hydrophilized.

[0021] Preferably, the pre-installed interfaces, especially the coated sleeves of the sensors, can be activated by ultraviolet (UV) irradiation. UV surface cleaning and / or activation with oxygen or ozone as reaction partners are also conceivable, allowing for optimized surface wetting. Compared to chemical methods using initiators, for example, the production process using UV irradiation is not expected to pose any health hazards. These components can be supplied as coated parts, preferably coated with a layer composed of titanium dioxide-based nanoparticles. Therefore, there is no need to provide suction devices or similar devices in production, thus keeping investment costs low. Therefore, the currently conventional manual / hand-processing can continue as is. Any organic residues on the sleeves are highly hazardous during the encapsulation process and can only be removed without leaving any residue using photocatalytic cleaning.

[0022] The purpose of the pre-treatment is to improve the wetting between the surface of the encapsulated component and the encapsulation, which improvement is due to an optimization, in particular a reduction, of the interfacial energy in the interface between the component to be encapsulated and the encapsulation material relative to the sum of the surface energy and the surface tension of the surface of the material to be encapsulated and the surface of the encapsulation. In particular, the contact angle between the surface of the component to be encapsulated, for example a metal surface, and the plastic used for the encapsulation can thus be reduced.

[0023] For the encapsulated metal sleeve, it is important that the sleeve is a component of a plug connector or a sensor. The construction made of the metal sleeve and the encapsulation is carried out according to the method according to the preceding features.

[0024] The same applies to a sensor (interface) according to the application, which can comprise an encapsulated metal sleeve, in particular a plug connector according to the preceding embodiments.

[0025] In view of the above statements, it is clear that the wetting described above is not the only thing that is improved by the UV irradiation. In fact, the photocatalytic combustion can achieve a cleaning effect.

[0026] The surface pre-treated in this way makes it possible, after encapsulation, for a sufficiently good adhesion to occur between the metal surface and the encapsulation material. The sleeve can be treated from the outside and / or from the inside. The UV light activation can also be carried out from the outside and / or from the inside.

[0027] The encapsulation method used can be a so-called thermal spray method within the scope of the plastic injection molding process. Depending on the requirements, casting and sintering are also possible.

[0028] The pre-treatment further ensures that the production runs are easy, robust, at the same time highly reliable and with significantly reduced waste. In terms of manufacturing technology, it is advantageous that the method can be implemented in the manufacturing process, i.e. in the existing manufacturing / assembly process. It must be ensured that the cycle time is not shortened. The exposure time required for the UV light activation can be chosen to be less than the production cycle, so that the throughput is not reduced.

[0029] Furthermore, the method does not involve additional costs in connection with occupational health and safety measures in production. The method can be easily implemented in existing production processes. The supplied metal parts, in particular the metal solid bodies delivered by external suppliers in the form of bulk material, can be installed as usual. The UV irradiation can be carried out inline before the actual encapsulation. The through-holes in the sleeve also contribute to ensuring the irradiation in the critical inner part of the sleeve, the bend. The time required for the UV irradiation is less than 100 seconds. Even longer irradiation times are not detrimental to the activation, but are undesirable for technical production reasons. Thus, if necessary, it can be checked whether the pre-treatment has produced the desired effect. Thereafter, the solid body, also referred to as injection-molded part, can be placed into the injection-molding tool and encapsulated and then set aside. The process is repeated in the following way: UV irradiation of the next injection-molded part and corresponding insertion.

[0030] The method is also more environmentally friendly, since there is no need for any type of extraction or disposal of, for example, the initiator (conventional adhesion promoter), some of which are highly toxic. The application of the titanium dioxide layer at the supplier is also environmentally friendly.

[0031] Furthermore, the storage capability of the respective manufactured part must be two years and more, and no special protective measures are required for storage and transport. This means that the effect of the pre-treatment, and ultimately the adhesion between the individual parts, is maintained over the period mentioned. An important factor for the qualification of the parts is the maximum permissible storage period without loss of function or visual change. In known methods, the activation of the metal is usually very unstable and therefore greatly limited in terms of time. It has been shown that the effect of photocatalytic self-cleaning can be completely reproduced and repeatedly restored by means of UV light irradiation. The technical agent preferably complies with the EU guidelines, RoHS "Restriction [on the use of certain] hazardous substances" and REACH - "Registration, Evaluation, Authorization and Restriction of Chemicals". BRIEF DESCRIPTION OF DRAWINGS

[0032] There are various possibilities for designing and developing the teachings of the present application in an advantageous manner. For this purpose, reference is made, on the one hand, to the claims and, on the other hand, to the following description of preferred exemplary embodiments of the application with reference to the accompanying drawings. The general preferred design and development of the teachings will also be explained with reference to the description of the preferred exemplary embodiments of the application with reference to the accompanying drawings. Shown in the drawings are the following:

[0033] Figure 1 is a schematic view of an exemplary embodiment of a plug connector encapsulated in plastic;

[0034] Figure 2 is Figure 1 is a detail view of the plug connector shown schematically in

[0035] Figure 3 is a schematic view of another exemplary embodiment of a plug connector encapsulated in plastic and having a cast seal. DETAILED DESCRIPTION

[0036] The figures together show a plug connector, which is for example encapsulated in plastic and comprises an insulating encapsulation 1 made of plastic, which is optionally a cast compound, and a molding 1'inside a sleeve 2, which has a metal surface 3. The sleeve consists of metal and is completely encapsulated by a surface 3 with photocatalytic properties. For this purpose, the surface 3 is treated photocatalytically over the entire area of the sleeve 2, i.e. on the outside and on the inside, and is thereby for example coated with titanium dioxide, so that the wettability of the plastic is improved. The surface 3 can be applied for example in an impregnation method or in other known ways. The adhesion of the injection-molded plastic of the encapsulation 1 on the surface 3 and in the area of the through-hole 4 of the sleeve 2 is promoted.

[0037] Figure 2 The plug connector based on which the details can be seen shows the same essential features as Figure 1 which makes further statements superfluous.

[0038] The following statements relate to the example of an injection-molded encapsulation using an insulating encapsulation 1 in accordance with the teachings of the present invention:

[0039] The underlying problem is that for a sleeve 2 encapsulated with plastic, especially in the context of a plug connector, it is difficult to permanently achieve a media-tight connection between the components. This is due to the aging processes of the materials and the different coefficients of thermal expansion, as well as the solidification stresses in the plastic.

[0040] The photocatalytic and photohydrophilic titanium dioxide layer on the surface 3 can be used to produce the following important properties / effects: cleaning, which also relates to organic pollutants; self-sterilization; anti-fog effect; hydrophilization; gas and liquid cleaning. Photocatalytic self-cleaning is also possible.

[0041] The method of producing a media-tight material composite works by means of plastic injection molding, especially in the context of the thermal spray method, in particular for media-tight encapsulation 1 depending on the process. In addition, the method can also be used as a cleaning method when evacuating, gluing, low-pressure casting, or for other shape substance connections.

[0042] The coated metal component or sleeve 2 can be stored for years without losing effectiveness, since the activation by means of UV radiation allows the photochemical effect to be reactivated. In order to pre-treat the surface in accordance with the method, the metal component with the titanium dioxide-coated surface 3 can be cleaned or activated by means of UV radiation - photocatalytic combustion or photo-induced hydrophilization - in a short time interval before encapsulation with the encapsulation 1, among other things.

[0043] According to Figure 3 The arrangement according to The arrangement according to

[0044] The ultraviolet irradiation is performed from the connection side, i.e. from above, so that the inner photocatalytic surface 3 of the sleeve 2 and the outer surface 3 of the connection side of the contact area are activated. Even if the metal of the sleeve 2 and the plastic of the encapsulation 1 have different expansion coefficients, the formation of gaps and micro cracks can be greatly reduced or prevented. Figure 3

[0045] With regard to other advantageous embodiments according to the teachings of the present application, reference is made to the general part of the description as well as to the attached claims, in order to avoid repetitions.

[0046] Finally, it is expressly stated that the above exemplary embodiments according to the teachings of the present application are only used to illustrate the present application and not to limit it to these exemplary embodiments.

[0047] List of reference signs

[0048] 1 encapsulation

[0049] 1' molded part

[0050] 2 sleeve

[0051] 3 surface

[0052] 4 through hole

Claims

1. A method of producing a media sealing material composite having a metal sleeve and an electrically insulating plastic at least partially surrounding the metal sleeve, wherein, - the surface (3) of the component with which the plastic comes into contact is pretreated in order to promote the adhesion of the plastic to the component, - wherein the pretreatment is a mechanical and / or chemical and / or physical pretreatment, characterized in that - the coated metal sleeve (2) is completely surrounded by a metal surface having photocatalytic properties, - the surface (3) is subjected to a photocatalytic treatment over the entire area on the outside and inside of the metal sleeve (2), and - the coated metal sleeve (2) of the preassembled interface is activated by means of UV irradiation.

2. The method of claim 1, wherein, - the metal sleeve is encapsulated by plastic.

3. The method of claim 1, wherein, - the metal sleeve is cast in plastic.

4. The method of claim 1, wherein, - the metal sleeve is encapsulated by sintering with plastic.

5. The method according to any one of claims 1 to 4, characterized in that, - the metal sleeve (2) is in at least partial direct contact with the plastic via a contact area, wherein the contact area is pretreated.

6. The method of claim 5, wherein, - the pretreatment comprises cleaning of the surface (3) of the metal sleeve.

7. The method according to claim 1 or 6, characterized in that, - the purpose of the pretreatment is to improve the wetting between the surface (3) of the metal sleeve and the plastic by optimization of the interfacial energy of the interface relative to the sum of the surface energies of the surface (3) of the material to be encapsulated by plastic and the plastic.

8. The method of claim 7, wherein, - the purpose of the pretreatment is to improve the wetting between the surface (3) of the metal sleeve and the plastic by optimization of the contact angle between the surface (3) and the plastic.

9. Metal sleeve (2) surrounding a component as a plug connector, produced according to the method according to any one of claims 1 to 8.

10. Sensor comprising a metal sleeve (2) surrounded by plastic according to claim 9.

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