US-12617135-B2 - Method for producing a media-tight material composite

US12617135B2US 12617135 B2US12617135 B2US 12617135B2US-12617135-B2

Abstract

A method for producing a media-tight material composite, in particular comprising a metal solid body and an optionally electrically insulating plastic at least partially surrounding the solid body, preferably as a component of a preferably shielded electrical interface, wherein surfaces of the solid body that the plastic contacts are subjected to a surface pretreatment in order to promote the adhesion of the plastic to the solid body. The disclosure further relates to a cylindrical metal sleeve, in particular as part of a plug connector, and a plug connector or sensory comprising a metal sleeve, produced by the foregoing method.

Inventors

Hans Michael Finke
Andreas Armin Neuner

Assignees

FRANZ BINDER GMBH + CO. ELEKTRISCHE BAUELEMENTE KG

Dates

Publication Date: 20260505
Application Date: 20200930
Priority Date: 20190930

Claims (12)

1 . A method for producing a media-tight material composite, comprising a metallic sleeve having outer and inner sides and a plastic at least partially surrounding the metallic sleeve, the method comprising: pretreating surfaces of the metallic sleeve contacted by the plastic by a pretreatment to promote an adhesion of the plastic to the metallic sleeve, wherein the pretreatment is a mechanical and/or chemical and/or physical pretreatment, wherein the metallic sleeve is part of a pre-mounted interface, wherein the metallic sleeve is completely surrounded with a metal surface which has photocatalytic properties, and wherein the metal surface is treated photocatalytically over the entire region of the metallic sleeve at the outer and inner sides, activating the metallic sleeve of the pre-mounted interface by way of UV radiation, and surrounding the metallic sleeve by the plastic.
2 . The method according to claim 1 , wherein surrounding the metallic sleeve comprises encapsulating the metallic sleeve with the plastic.
3 . The method according to claim 1 , wherein surrounding the metallic sleeve comprises casting the metallic sleeve with the plastic.
4 . The method according to claim 1 , wherein surrounding the metallic sleeve comprises encasing the metallic sleeve by sintering with the plastic.
5 . The method according to claim 1 , wherein the metallic sleeve at least partially has direct contact with the plastic via a contact region, wherein said pretreating surfaces of the metallic sleeve comprises pretreating the contact region.
6 . The method according to claim 5 , wherein pretreating the contact region comprises cleaning the contact region.
7 . The method according to claim 1 , wherein the pretreatment improves a wetting between the surfaces of the metallic sleeve and the plastic, resulting from an optimization of an interface energy of the interface.
8 . The method according to claim 1 , wherein the plastic is an electrically-insulating plastic.
9 . The method according to claim 1 , wherein the metallic sleeve and the plastic at least partially surrounding the metallic sleeve is a component of an electrical plug.
10 . The method according to claim 9 , wherein the electrical plug is a shielded electrical plug.
11 . The method according to claim 9 , wherein the metallic sleeve and the plastic at least partially surrounding the solid body forms a plug sleeve of the electrical plug.
12 . The method according to claim 7 , wherein the optimization is an optimization of a contact angle between the surfaces of the metallic sleeve and the plastic with respect to a sum of surface energies of the surfaces of the metallic sleeve and the plastic.

Description

BACKGROUND Technical Field The disclosure relates to a method for producing a media-tight material composite, in particular a media-tight arrangement of a solid body surrounded by plastic, and further in particular, an electrical plug connector that is preferably shielded. Furthermore, the disclosure relates to a preferably cylindrical metallic sleeve, in particular, as a component of a plug connector. Finally, the disclosure relates to a plug connector or sensor, comprising a metallic sleeve. Description of the Related Art Numerous applications are available for use in encapsulated plugs, of which the sensor region and/or the outdoor region are merely referenced by way of example. In accordance with the specific field of application, high demands are placed on the tightness of such plugs. This is referred to as the need for a media-tight encapsulation. Depending upon the protection class—in particular, with IP67, IP68 or IP69K—the encapsulation can be the last operation before completion. In the case of a leak, the entire previous added value becomes worthless, and an encapsulated plug, for example, becomes a reject. In the case of external application (outdoor plug, HEC), tightness is even more important, and increased demands on the materials and/or material composites ensue. This may be the need for increased tightness, e.g., protection class 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, there may be increased demands with respect to maximum weather resistance—for example, against UV irradiation and/or sprinkling. It is known from practice that media-tight encapsulations can be realized well for freshly-molded parts. However, if the parts age, gaps are formed due to shrinkage in the boundary layer between, for example, a metallic sleeve and the encapsulation. Due to a hygroscopic effect, moisture penetrates the component through the gap. In addition to the aging processes, different coefficients of expansion of the metal and of the encapsulation material, which are usually made of plastic, are responsible for the formation of cracks. Further important influencing criteria are the materials or their combination, the component geometries, the production method, the tool design, and the corresponding process management. Material factors in the failure of media-tight material composites are the formation of gaps and the occurrence of micro cracks in the plastic component, which are substantially attributable to a lack of adhesion between the metal and plastic components, but also to mechanical solidification stresses. BRIEF SUMMARY AND GENERAL DESCRIPTION The present disclosure specifies a method according to which regions surrounded by plastic are media-tight over a long period of time as well. This should apply, in particular, to the interfaces between the usually metallic component and the plastic, in particular as a component of a plug connector. Preferably, crack-free and gap-free encapsulation and improved adhesion of the metal-plastic compound are to be realized. Finally, a corresponding interface having a metal sleeve surrounded by plastic is to be specified, which is produced by the method according to the disclosure. It should be noted at this juncture that the solid body or the metal part can be surrounded by plastic by means of different methods. An injection molding process is mentioned below merely by way of example, without being limited thereto. According to the disclosure, a media-tight plastic coating is produced around a solid body, and in particular around components of a preferably shielded electrical plug, which can be a component of a sensor, for example. According to the disclosure, surfaces of the components contacted by the plastic are pretreated to promote the adhesion of the plastic to the components. The disclosure is based upon the idea of establishing, during the manufacturing process, an improvement in the wetting between the metal part and the plastic, which results from an optimization of interface energy in relation to the surface energies or surface tensions of the respective components. Ultimately, this involves optimizing the contact angle during wetting. Due to sufficiently good adhesion, the gap formation between the metal surface and the plastic is effectively minimized/avoided even over longer use, and even where the components have different coefficients of expansion. The is advantageous for the product in that the media-tight material composite becomes much more robust. As a result, sufficient tightness can also be ensured under adverse conditions. According to one embodiment, the solid body is encapsulated with plastic, for example, with polyurethane. Encapsulation takes place after pretreatment, and in particular directly after pretreatment. Since the result of the encapsulation is strongly dependent upon the adhesion/cleanliness of the plastic on the