FR2785297A1 - Plastic-coated metal support with an energy saving galvanic contact zone for components to be electrolyzed - Google Patents

Abstract

A metal support (1) with a galvanic contact zone for a component to be electrolyzed, the support being at least coated with a layer of an insulating plastic (4), is characterized in that at least one energy saving layer (2) of galvanic contact is applied on the galvanic contact zone between the support and the plastic insulation in order to prevent the hooking of the insulating plastic on the galvanic contact zone. The energy saving layer is a silicon elastomer. A rendering of an adherence primer (3) may be effected before or after the application of the energy saving layer. An Independent claim is also included for a method of producing this metal support (1) with a galvanic contact zone and comprises the following steps: (a) the surface of the metal support is prepared; and (b) at least one layer of the energy saving material is applied on the galvanic contact zone of the support.

Description

 The present invention relates to a saving by silicone elastomer for plasticized metallic support with galvanic contact, as well as a corresponding production method. It has applications in the field of electrolysis and relates more particularly to the metal supports of parts to be treated in electrolysis baths.

 The treatment by electrolysis of metallic and / or plastic parts rendered electrically conductive requires the use of extremely corrosive electrolysis baths which can generate vapors or gases which are themselves corrosive.

 The parts to be treated are maintained or supported by a metal tool which has a complex shape and structure and which consists of chassis comprising a multitude of electrical contacts, for example of the hook or spring clip type. Such tools will subsequently be called galvanic support. The galvanic support, in addition to its holding rail or support, is also used to transmit the electric current to the part to be treated. An electrical contact must therefore be ensured between the galvanic support and the part to be treated. This contact can possibly be facilitated by active devices of the spring clip type made of stainless steel or titanium.

Thereafter, we will call the contact zone, galvanic contact zone. This galvanic support may include a hook, a straight clamp, a clip clamp, a self-clamping clamp or even a jaw clamp.

 The galvanic support, being in this corrosive environment, is generally protected and insulated chemically and electrically by one or more layers of a plastic coating. This coating is generally of the vinyl plastisol0 type. The metal support is covered with plastic material generally by soaking at high temperatures.

 However, before using the plasticized metal support, it is necessary to remove the plastic from the galvanic contact zone, to strip it, so that the current can be transmitted to the part to be treated. However, so that the plastic coating can play its protective role, the adhesion between the plastic coating and the metal support is very important. In addition, the contacts can have complex shapes.

 The stripping of the galvanic contact area is therefore complex, even impossible in certain inaccessible areas. Furthermore, this stripping operation can weaken the plastic coating which must remain on the rest of the support in order to protect it.

 In order to prevent plastisol0 from covering the galvanic contact area, it has been proposed to protect it with a product before soaking.

The products intended to protect the galvanic contact zone can be waxes or varnishes, molten metal salts, sheaths or sleeves of specific sizes and shapes or even heat-shrinkable, aluminum or crepe paper. However, the various prior art solutions have drawbacks and are difficult to implement.

The products intended to protect the galvanic contact area do not adhere perfectly, air can be trapped, the products are not stable with respect to the temperatures used and / or to the other products used, including plastisol @.

 The present invention therefore proposes to remedy these drawbacks by means of a metal support with a galvanic contact zone for a part to be electrolyzed, said support being at least covered with one or more layers of a plastic insulator.

 According to the invention, at least one layer of galvanic contact savings is applied to the galvanic contact zone between the support and the plastic insulator, in order to prevent the plastic insulator from catching on the contact zone. galvanic, said savings being a silicone elastomer.

In various embodiments of the invention, the following means can be considered according to all the technically possible combinations are used:
-the galvanic contact savings are of the Rubson type;
The invention also relates to a method for producing a metal support with a galvanic contact zone for a part to be electrolyzed, said support being covered with a plastic insulator.

According to the process invention:
a preparation of the surface condition of the metal support is carried out;
-at least one layer of galvanic contact is applied to the galvanic contact area of the support, said savings being a silicone elastomer.

In various forms of implementation of the process invention, the following means can be considered according to all technically possible combinations:
-the silicone elastomer is dried.

- a coating of an adhesion primer is applied to the;
- the support is covered with at least one layer of plastic insulation by soaking;
-the plastic insulation is secured
-) The coating of an adhesion primer on the support is carried out before the application of the silicone elastomer;
The coating of an adhesion primer on the support is carried out after the application of the silicone elastomer;
- the galvanic contact area is stripped by peeling or brushing.

 -the plastic insulation, the adhesion primer and the silicone etastomer are removed from the contact zone by peeling or brushing.

-the galvanic contact savings are applied by;
-the galvanic contact savings are applied by spraying;
-the galvanic contact savings are applied manually with a brush.

 The invention allows the simple and efficient installation of a galvanic contact savings. The stripping of the contact is simple and does not require any toxic product or heat. The product is economical and waterproof and can solidify at room temperature. The product is stable and resistant to the temperatures used. It does not contaminate other products including adhesion primer and plastisol0.

The present invention will be better understood by the description of a preferred embodiment of a plasticized metal support according to the principle of the invention using a galvanic contact savings and by the description of the appended figures in which:
FIG. 1 shows in section a metal support with a galvanic contact area of the hook type after preparation of the surface finish;
FIG. 2 represents the support of FIG. 1 after application of the galvanic contact savings;
FIG. 3 represents the support of FIG. 2 after coating with an adhesion primer;
FIG. 4 represents the support of FIG. 3 after covering with a layer of a plastic insulator; and
FIG. 5 represents the support of FIG. 4 after stripping of the galvanic contact zone.

 The preferred embodiment of a metal support with galvanic contact for a part to be electrolyzed is as follows. In this example, a hook type support is used, but the invention is applicable to any type of passive or active support (comprising for example a spring).

 In a first step, the support undergoes preparation of its surface condition by mechanical treatment. Preferably, shot peening or sandblasting of the surface of the support is used. A chemical treatment completes this step and consists of degreasing the support. Finally, the support is rinsed and dried, preferably in an oven around 200 C. The support 1 with galvanic contact thus treated, a hook, is shown in section in FIG. 1.

 In a second step, an adhesion primer is deposited on the support by coating. The role of this primer is to promote adhesion to the support of the insulating plastic coating. This adhesion primer is an acrylic polymer dispersed in solvents. The adhesion primer is compatible with polyvinyl chloride. The coating can be done by soaking, by spraying, or even manually with a brush. The solvent (s) in the adhesion primer are removed by evaporation, preferably by preheating in a ventilated oven between approximately 180 to 200 for 15 to 20 minutes, these temperatures being variable depending on the size of the surface of the support, its shape or other features.

These values, as well as the following, are approximate and given for information only.

 The application of the galvanic contact savings can be carried out directly after the first stage or even after the second stage, therefore on the adhesion primer. In FIGS. 2 and 3, the saving 2 of galvanic contact is applied before the coating of an adhesion primer 3.

The savings are preferably a silicone elastomer and are preferably of the Rubsone type. The application of the savings can be done by soaking in the silicone elastomer or by manual application. This application will only concern the galvanic contact area.

 The silicone elastomer solidifies with ambient air or by heating in a ventilated oven. In the case where the silicone elastomer is applied after the second step consisting in coating an adhesion primer, solidification will be favored by preheating in a ventilated oven.

 The final step in producing the insulating plastic coating consists in dipping the support treated according to the preceding steps in a tank containing plastic material, preferably plastisol @. The support is reassembled out of the soaking tank at the rate of 1 cm / minute. The gelling and baking of the plastic material are obtained for 45 to 60 minutes at around 180 in a ventilated oven. The support thus treated is finally cooled with ambient air. A support thus treated is shown in Figure 4 with a single layer of plastic insulation 4. Although this example relates to a layer of insulating plastic, it is envisaged the case where several layers of insulating plastic, possibly with different properties, are carried out.

 A part thus treated is completely covered with insulating plastic. It can be delivered directly to the end user who will eliminate, by simple peeling or brushing, the insulating plastic material, the adhesion primer, the silicone elastomer being at the level of the galvanic contact, the latter then being in a state perfect surface for immediate application to electrolysis. A support with stripped galvanic contact area is shown in Figure 5.

 However, it is also envisaged that the insulating plastic, the adhesion primer, the silicone elastomer are removed by peeling or brushing after the support has been produced and that the end user receives the support with the stripped galvanic contact area.

 In the case where the adhesion primer is directly placed on the metal support before application to save galvanic contact, a possible cleaning of the galvanic contact area with a wire brush may be necessary, in order to completely eliminate the adhesion primer.

Due to the components used, there is no chemical reaction between the acrylic primer and the silicone elastomer, as there is between the insulating plastic material and the silicone elastomer. The silicone elastomer will be chosen according to the characteristics of the process for producing the metal support and, in particular, the temperatures reached and the duration of these stages. If a long preheating or prolonged and / or high temperature cooking is necessary, a high temperature silicone elastomer of the Versifie type will be chosen *
Thanks to the presence of the silicone elastomer at the level of the galvanic contact zone, the insulating plastic material, preferably plastisol @, does not adhere to the metal support and can therefore be easily removed.

 The description of an embodiment of the invention as just described is purely indicative and should not limit the scope of the invention.

Claims (9)

 1. Metal support (1) with galvanic contact zone for part to be electrolyzed, said support being at least covered with a layer of plastic insulator (4), characterized in that at least one layer of a savings (2 ) of galvanic contact is applied to the galvanic contact zone between the support and the plastic insulator in order to prevent the attachment of the plastic insulator to the galvanic contact zone, said savings being a silicone elastomer.  2. Support according to claim 1, characterized in that the saving of galvanic contact is of the Rubson @ type.  3. Method for producing a metal support (1) with a galvanic contact zone for a part to be electrolyzed, said support being covered with a plastic insulator, characterized in that:  a preparation of the surface condition of the metal support is carried out;  at least one layer of a galvanic contact spar (2) according to any one of the preceding claims is applied to the galvanic contact zone of the support, said spar being a silicone elastomer.  4. Method according to claim 3, characterized in that it further comprises the following steps:  a coating of an adhesion primer (3) is made on the support;  - the support is covered with at least one layer of a plastic insulator (4) by soaking;  -the plastic insulation is secured  5. Method according to claim 4, characterized in that the coating of the adhesion primer is carried out before the application of the galvanic contact savings.  6. Method according to any one of claims 3 to 5, characterized in that the galvanic contact area is stripped by peeling or brushing.  7. Method according to any one of claims 3 or 6, characterized in that the saving of galvanic contact is applied by dipping.  8. Method according to any one of claims 3 to 7, characterized in that the galvanic contact savings is applied by spraying.  9. Method according to any one of claims 3 to 8, characterized in that the contact savings is applied manually with a brush.