WO2007090625A1

WO2007090625A1 - Plastic container having at least one electrode made of electrically conductive plastic

Info

Publication number: WO2007090625A1
Application number: PCT/EP2007/001037
Authority: WO
Inventors: Marlene Rinner; Fabrizio Civetta
Original assignee: Röchling Automotive AG & Co. KG
Priority date: 2006-02-07
Filing date: 2007-02-07
Publication date: 2007-08-16
Also published as: DE102006005529B4; DE102006005529A1

Abstract

A plastic container (10) comprises a container body (12) and an electrically conductive electrode device (28) which is arranged on the container body (12) in such a manner that at least one section (34) of the electrically conductive electrode device (28) is exposed inside (26) the container body (12) in order to be contact-connected by material which has been poured or can be poured into the container body (12), wherein at least sections of the electrically conductive electrode device (28) are formed from electrically conductive plastic.

Description

Plastic container with at least one electrode made of electrically conductive plastic

description

The present invention relates to a plastic container having a container body and having an electrode means disposed on the container body such that at least a portion of the electrically conductive electrode means for contacting by material filled or filled in the container body is exposed inside the container body.

The container body surrounds a certain volume of space into which material can be introduced through an opening in the container body. In the case of electrically conductive materials, the material level in the container body can be detected by an electrically conductive electrode device. For this purpose, the electrode device must have at least two electrodes of different electrical potential, which are only electrically connected to one another by the material filled into the container body. Depending on whether or not the at least two electrodes of different potential are electrically conductively connected to one another by the filled material, a minimum filling level in the container body can be detected with a corresponding arrangement of the electrode device relative to the container body.

If the electrode device is mounted on the container body in such a way that it dips differently depending on the level of the material filled into the container body, the electrical resistance existing between the electrodes changes with the filling level, so that when the minimum filling level is exceeded in the container body, from which a contacting of the electrode device by the filled material, by measuring the electrical resistance between the electrodes on the Material level in the container body can be closed.

Such plastic containers are used, inter alia, in the automotive industry as a resource container, in particular as a spray water container for the windshield and windshield wiper cleaning or as Kühlwasserausgleichsbehälter.

The electrode devices known from the prior art comprise metallic electrodes, which are generally elongated and protrude into the interior of the container body.

A disadvantage of the known from the prior art solution is, first, that it comes through the flow of current between the metallic electrodes of the known electrode devices over the operating time to an electrolysis, which in turn leads to deposits of the

Electrolysis separated components of the filled into the container body material leads. The result is changing operating characteristics of the electrode device with increasing deposition and undesirably increasing the reliability of the detection result with the operating time.

In addition, the known electrode devices are often attached to the container body in such a way that they pass through from the outside to the inside, which leads to a considerable outlay for the sealing of the container body at the points of penetration. Even if the metal electrodes are encapsulated in a container body produced by injection molding during its production, this compound is not tight over the entire expected life of the plastic container, so that additional seals, such as O-rings, must be used to increase the sealing effect. For this purpose, appropriate sealing seats are provided on the metallic electrodes.

It is therefore an object of the present invention, a technical teaching specify how plastic containers of the type mentioned can be produced with significantly lower cost while improving the quality of reliability, tightness and service life.

This object is achieved by a generic plastic container, wherein the electrically conductive electrode device is at least partially formed of electrically conductive plastic.

It has been shown that, compared with the case of metallic electrodes, the electrolysis-related deposits on the electrodes when using the same filled in the container body materials of electrically conductive plastic fail or even can be completely avoided. As a result, the detection result of the electrode device in which electrically conductive resin is exposed in the container body interior for contacting the material filled in the container body with reliable, small changes over the entire service life of the plastic container, and thus of higher accuracy than in the metallic electrodes of the state of the technique.

In a particularly simple case it can be provided that the electrode device is attached to a wall of the container body. The electrode device particularly preferably passes through a wall of the container body, since the contacting of electrodes through material filled into the container body can take place at the portion of the electrode device located in the interior of the container body, and a potential may flow between the electrodes when the voltage is applied to the electrodes of the electrode device Current can be conveniently detected at the located outside of the container body portion of the Elektrodeneinrich- device.

For this purpose, provision can be made, in particular, for the electrode device to have a connecting strip made of electrically conductive plastic. has cut, which is designed for contacting by an electrical line. Particularly preferably, this connection section is formed integrally with at least one electrode of the electrode device. In contrast to the metallic electrodes of the prior art, in which an elaborate, usually machining machining is required, in the case of electrodes made of conductive plastic, the connection section can already be formed during the initial shaping of the electrode device or its respective electrode.

In the case of the arrangement of the electrode device passing through a wall of the container body, a further advantage of the use of an electrode device, which is formed at least in sections from electrically conductive plastic, clearly comes into play. Compared to the plastic-metal material pair used in the prior art between container body and electrode device, the material properties of the plastic-plastic material pairing used in a plastic container according to the present invention are less different, so that the provision of additional sealing devices, such as Rings and the like, can be dispensed with. Rather, diffusion processes or fusion processes may occur between the container body and the electrically conductive plastic of the electrode device, independently of the manufacturing method used to produce the plastic container, which at least partially lead to a cohesive connection of the electrically conductive plastic of the electrode device with the plastic of the container body can lead. Even if this is not the case, however, the difference between the respective thermal expansion coefficients of the electrically conductive plastic and the plastic of the container body is substantially lower than in the metal-plastic material pair used in the prior art, so that thermally induced relative movements between electrode device and container body lower than in known Kunststoffbehältem, which increases the tightness of an interspersed by electrode container body. At least one electrode, preferably all electrodes, of the electrode device of the plastic container according to the invention are preferably designed as elongate components which extend along an electrode longitudinal axis. This has the advantage that the container body, as described above, can be penetrated by at least one electrode, preferably by all the electrodes, and on the electrodes themselves a sufficiently long section is available, at which they can be enclosed by the plastic of the container body , The longer the area enclosing the electrodes can be formed in the direction of the longitudinal axis of the electrode, the better the container body can be at the point of penetration of the electrode device due to the increasing sealing surface without the use of additional sealing means formed separately from the container body and the electrode arrangement, such as sealing rings, sealed against leakage.

The elongated electrode preferably has the above-described connection section in the region of its longitudinal end lying outside the container body, so that a sufficiently long electrode can be produced with the lowest possible requirement for electrically conductive plastic.

It may be thought to form only a few portions of an electrode of the electrode device made of electrically conductive plastic. However, it is simpler and cheaper to use such an electrode in the

Essentially completely made of electrically conductive plastic. In this case, the electrode can be formed as needed in the desired shape by suitable Urformwerkzeuge. "Substantially complete" is not intended to exclude that small amounts of other materials, such as contact shoes on the terminal portions and the like, may be provided on the electrode of the electrode device in question. The above-mentioned diffusion processes or merging processes between the material of the container body and the electrically conductive plastic of the electrode device, which lead to increased tightness of a container body of the plastic container penetrated by at least one electrode, can then be effected particularly simply if the container body forming the container body Plastic and at least a portion of the electrically conductive electrode device forming electrode-plastic compatible or have the same polymers. ^'

With a view to achieving the best possible sealing of the container body penetrated by at least one electrode at the point of penetration, the electrically conductive plastic comprises a polymer matrix and electrically conductive particles incorporated therein, wherein the plastic of the polymer matrix and the container body Plastic compatible or even identical.

In principle, the electrode device may comprise only a single electrode component which is exposed in the container body, if the latter has galvanically separated electrode elements of different electrical potential. However, such an electrode component is less preferred, since its production is very complicated. A preferred embodiment of a plastic container according to the present invention comprises two spaced-apart electrically conductive electrodes, both of which are at least partially made of electrically conductive plastic and both are arranged on the container body, that in each case at least a portion of the electrically conductive electrodes in the interior of the container body is exposed.

In principle, the plastic container described above can be produced by any desired manufacturing method. For example, the electrodes of the electrode device and the container body can be manufactured in separate manufacturing processes and subsequently assembled together become. However, such a production method would not make optimum use of the essential advantages of the plastic container according to the invention.

Furthermore, it may be thought to manufacture the electrodes of the Elektrodeneinrich- device separately from the container body and insert it into a master mold for the production of the container body. The plastic molding compound forming the container body could then flow around the electrodes provided, wherein the plastic molding compound is usually thermally softened to form the container body and due to the elevated temperature of this molding compound the previously mentioned advantageous diffusion processes or fusion processes between the provided plastic Electrodes and the enclosing plastic container body section could use.

It should be emphasized at this point again emphatically that a significant advantage of the present invention is the fact that on the container body, a holding portion may be formed which one electrode or preferably all electrodes of the electrode assembly without an intermediate arrangement of separately formed sealing means, in particular Sealing rings and the like, fluid-tight surrounds. In this case, since the plastic containers described in the present application are generally designed for receiving and storing liquid, a liquid-tightness at the holding portion of the container body is sufficient.

However, it is particularly preferred to produce the container body and at least one electrode, preferably all electrodes, essentially simultaneously or in a short time sequence by a multi-component injection molding process, preferably by a two-component injection molding process. In this case, a stable cohesive connection between the at least one electrode made of electrically conductive plastic and the plastic of the container body can be achieved particularly easily, in particular if that for the electrodes and for the container body plastics used are based on the same or at least one compatible polymer base.

The electrodes of the electrode device can have any desired cross-sectional shape.

The above-described preferred production method (multi-component injection molding method) therefore likewise represents a solution according to the invention of the object on which the present invention is based.

The present invention will be explained in more detail below with reference to the accompanying drawings. It shows:

1 shows a first embodiment of a plastic container of the present invention and

Fig. 2 shows a second embodiment of a plastic container of the present invention.

In Fig. 1, a first embodiment of a plastic container according to the invention is generally designated 10. In the example shown in FIG. 1, the plastic container 10 is a splash water tank for a windscreen washer system of an automobile. The plastic container 10 comprises a container body 12 comprising a lower shell 12a and a sealing shell 12b sealingly connected thereto.

The container body 12 has a discharge opening 14 and a filling opening 16. Furthermore, an additional opening 18 is provided, which can be used for example for material and / or pressure equalization.

The filling opening 16 is provided with a thread 20 into which a cover, not shown, can be screwed to close the filling opening 16. The remaining openings 14 and 18 are used as hose plug neck 22 or 24 designed. In the interior 26 of the container body 12, an electrode assembly 28 extends with two electrodes 30 and 32 made of electrically conductive plastic. The electrodes 30 and 32 are formed identically, which is why it is sufficient in the following to describe only the left in Fig. 1 electrode 30 representative of the electrode 32.

In the example shown in FIG. 1, the electrode 30 extends in a rod-shaped manner along an electrode longitudinal axis ELA.

The electrode 30 comprises a detection section 34 which extends from its longitudinal end 30a located in the interior 26 of the container body 12 to slightly beyond the longitudinal center of the electrode 30. Adjoining the latter in the direction of the electrode longitudinal axis ELA is a connecting region 36, along which the electrode 30 is surrounded in a sleeve-like manner by the material of the lower shell 12a of the container body 12. The longitudinal end region 38, which adjoins the connection section 36 in the longitudinal direction of the electrode longitudinal axis ELA and extends up to the longitudinal end 30b of the electrode 30 located outside the container body 12, is designed as a connection section onto which an electrical contact at the end of an electrical line for contacting the electrode 30 is plugged.

The electrodes 30 and 32 as well as the lower shell 12a and the upper shell 12b of the container body 12 comprise the same polymer material. This is used only for the container body 12 unfilled and filled for the electrodes 30 and 32 with electrically conductive particles.

Along the connecting portion 36, sleeves 40 formed on the lower shell 12a are materially connected to the electrodes 30 and 32 and thus ensure a good sealing of the lower shell 12a on the

Place where this is penetrated by the electrodes 30 and 32. The sleeves 40 constitute a previously mentioned holding section of the container body 12. The cohesive connection is produced almost simultaneously lower shell 12a and electrode means 28 produced by a per se known two-component injection molding process. Diffusion processes and / or merging processes on the electrodes 30 and 32, which are still warm after the injection molding process, and sleeves 40 result in the formation of a sealing connecting layer between them. However, even if this compound layer is not formed completely or even not formed, the two-dimensionally applied to the electrodes 30 and 32 sleeves 40 seal the lower shell 12 a against leakage, since the electrodes 30 and 32 and the lower shell 12 a through the use of the same or have at least one compatible thermoplastic polymer material substantially the same or at least very similar material properties, in particular thermal expansion coefficients, so that hardly a sealing endangering relative movements between the electrodes 30 and 32 and the sleeves 40 occurs during thermal load changes.

By way of the connection sections 38 and 39 of the electrodes 30 and 32, an electrical voltage can be applied to the electrodes 30 and 32 by means of a plug 42, which is not shown in the receptacle body 12, and these then have a different electrical potential. By measuring the electrical resistance between the electrodes 30 and 32 (for example, by measuring the voltage drop between them), at least the presence of a minimum filling quantity in the container body 12 can be concluded. If the electrodes 30 and 32 are wetted by electrically conductive liquid, the detected resistance decreases to a finite value.

2, a second embodiment of the present invention is shown. The same components as in FIG. 1 are denoted by the same reference numerals but increased by the number 100. For an explanation of these components, reference is expressly made to the description thereof in connection with FIG. The embodiment of FIG. 2 differs from that in FIG. 1 substantially by the shape of the electrodes 130 and 132 of the electrode assembly 128. The electrode 130 is angled in FIG. Also, the electrodes 130 and 132 are manufactured together with the lower shell 112a in the two-component injection molding process.

Also, the electrode 132 passes through the lower shell 112 a of the container body 112, wherein it is formed as the electrode 130 angled. Its connection section is hidden in FIG. 2 by the connection section 138 of the electrode 130.

Claims

claims

A plastic container (10; 110) comprising a container body (12; 112) and electrically conductive electrode means (28; 128) disposed on the container body (12; 112) such that at least a portion (34; 134) in the interior (26; 126) of the container body (12; 112) for contacting by material filled or to be filled into the container body (12; 112), characterized in that the electrically conductive electrode means (28 128) is at least partially formed of electrically conductive plastic.

A plastic container according to claim 1, characterized in that the electrode means (28; 128) is fixed to a wall of the container body (12; 112).

3. Plastic container according to claim 2, characterized in that at least one electrode (30, 32;

130) of the electrode means (28; 128) passes through the wall of the container body (12; 112).

4. Plastic container according to claim 3, characterized in that the electrode device (28, 128) has a connection section (38, 39, 138) made of electrically conductive plastic, which is designed to be contacted by an electrical line.

5. Plastic container according to claims 3 and 4, characterized in that the electrode device (28; 128) at least one electrode (30, 32; 130, 132) which extends along an electrode longitudinal axis (ELA), wherein a a first longitudinal end (30a; 130a) of the electrode (30; 130) in the interior (26; 126) of the container body (12; 112) and a second first longitudinal end (30b; 130b) of the electrode (30; 130) outside the first Container body (12; 112) is located and the connecting portion (38; 138) in the region of the second longitudinal electrode end

(30b, 130b) is formed.

6. Plastic container according to one of the preceding claims, characterized in that at least one electrically conductive electrode (30, 32, 130, 132) of the electrode device (28, 128) in

Essentially formed entirely of electrically conductive plastic.

Plastic container according to one of the preceding claims, characterized in that the container body plastic forming the container body (12; 112) and the at least one portion (34, 36, 38; 134, 138) of the electrically conductive electrode means (28; 128) have forming electrode-plastic compatible or the same polymers.

8. Plastic container according to claim 7, characterized in that the electrically conductive plastic comprises a polymer matrix and incorporated therein electrically conductive particles, wherein the plastic of the polymer matrix and the container body plastic are compatible or identical.

9. Plastic container according to one of the preceding claims, characterized in that the electrode device (28, 128) comprises two spaced apart electrically conductive electrodes (30, 32, 130, 132), both of which are at least partially made of electrically conductive plastic and both of which are arranged on the container body (12; 112) in such a way that in each case at least one section (34; 134) of the electrically conductive The electrodes (30, 32, 130, 132) are exposed in the interior (26, 126) of the container body (12, 112).

10. Plastic container according to one of the preceding claims, characterized in that the container body (12; 112) has a

Holding portion (40; 140) which surrounds an electrode (30, 32; 130, 132) of the electrode assembly (28; 128) without interposition of separate sealing means, in particular O-rings and the like, fluid-tight.

A method of making a plastic container (10; 110) according to any preceding claim, wherein the container body (12; 112) and the at least one electrode (30,32; 130,132) are formed by a multi-component injection molding process, preferably by a two-part injection molding process Component injection molding, to be produced.