EP1695768A1 - Process for temporary protection of bare surfaces against corrosion, and element with temporary corrosion protection - Google Patents

Abstract

For the temporary prevention of corrosion on blank metal surfaces (11.1), of a metal component (10), a protective film (12) against corrosion is applied to the metal surface. This is followed by a layer (13) of a self-repairing semi-solid material to cover the film at least partially. The semi-solid and/or protective film contain hydrophobic constituents to prevent the penetration of moisture to the metal surface When the component is to be used, the films are peeled off.

Description

The invention relates to a method for temporary protection of bare surfaces against corrosion and a component with a surface protected against corrosion.

State of the art

Corrosion is a known problem. There are several approaches to prevent or reduce corrosion. For example, the flow of electrons may be interrupted by changing the chemical composition of the materials involved, or by separating the material to be protected from corrosion from the electrolyte (for example, salty water). For example, there are also methods based on the use of a protective layer or a protective overcoat, the use of a rust preventing agent, or the use of surface passivation. Such protective layers are typically based on paints, organic coatings, ceramic and inorganic coatings, plastic coatings, precious metal deposits, etc. Other coatings, such as zinc, aluminum and magnesium based metals, are characterized by the tendency to accelerate to corrode as the surface to be protected (these layers are therefore also referred to as sacrificial layers). Anti-rust agents typically alter the surface chemistry and form a kind of intermediate layer. By contrast, the surface passivation mentioned at the beginning is typically done by applying or producing an oxide layer.

The methods mentioned are suitable essentially for permanent protection.

But there is also the need to protect bare metal surface only temporarily. For example, there are semi-finished or finished products that have a bare metallic surface that needs to be protected after production and until final use. As an example, drive shafts, tooth flanks on gears, rails, and the like are called. It is important that a protective agent applied quickly and easily and later removable again. However, the approaches mentioned above are only of limited use when it comes to protecting a bare metal surface temporarily.

Two different methods have been proven in practice, although these methods have disadvantages.

Usually, a bare surface is protected by a corrosion inhibitor which is applied or sprayed onto the surface. In machine and vehicle construction and in machinery, for example, a means is used for this purpose, which is marketed under the name Tectyl®. This agent is characterized by a good corrosion protection, but has the disadvantage that it is difficult to remove. Especially in elevator construction, where guide rails are used for the elevator car or the counterweight whose treads must be absolutely smooth and clean, such a protective means, which can be removed without residue again only with effort, only conditionally.

The use of solvents to expose the bare surface also has disadvantages, since these solvents can be environmentally harmful and therefore expensive to handle.

The sacrificial layers mentioned at the outset are also unsuitable for temporary protection since they have the disadvantage that they form an intimate connection with the surface to be protected are received and no longer, or only with great editing effort, are removable again. In addition, they change the properties of the bare surface and thus can not be used in guide rails, drive shafts and the like.

It is therefore the object of the invention to provide an approach which makes it possible to protect bare surfaces, in particular bright metallic surfaces, simply and effectively against corrosion, whereby these surfaces should be exposed again without residue after some time.

A first method according to the invention can be found in the independent claim 1. The method is characterized in that protecting bare surfaces against corrosion is a multilayer protection system used, which is applied in the following steps and removed if necessary. A corrosion protection film is applied to a bare surface to be protected. This corrosion protection film is at least partially covered by the application of a self-healing, semi-solid protective layer. These two layers form the multilayer protection system. If necessary, the protection system is removed again. At least a portion of the bare surface is exposed by peeling off at least a portion of the anti-corrosion foil. At the same time, the protective layer is removed with the anti-corrosion foil.

A component with a protected according to the invention against corrosion surface can be found in the independent claim 14

According to the invention, the self-healing protective layer forms a closed film and the protective system comprises hydrophobic components to prevent moisture from penetrating to the bare surface to be protected.

Further advantageous embodiments can be found in the dependent claims.

Particularly advantageous for the temporary protection of a guide rail of an elevator installation is the method claimed in claim 13, since only the running surfaces of the guide rails are exposed with this method.

Fig. 1

eine schematische, perspektivische Ansicht eines Teils einer Führungsschiene mit einem Schutzsystem gemäss Erfindung;

Fig. 2A

eine schematische, perspektivische Ansicht eines Teils einer Führungsschiene mit einem Schutzsystem gemäss Erfindung, wobei eine mechanische Beschädigung aufgetreten ist;

Fig. 2B

eine schematische, perspektivische Ansicht der in Fig. 2A gezeigten Führungsschiene nachdem die mechanische Beschädigung ausgeheilt ist;

Fig. 3A

eine schematische, perspektivische Ansicht eines Teils einer Führungsschiene mit einem Schutzsystem gemäss Erfindung, wobei die Korrosionsschutzfolie nur die zu schützende Oberfläche abdeckt;

Fig. 3B

eine schematische, perspektivische Ansicht der in Fig. 3A gezeigten Führungsschiene nachdem die Korrosionsschutzfolie entfernt und dadurch die zu schützende Oberfläche freigelegt wurde.

The invention will now be described in detail by way of examples and with reference to the drawings. Show it:

Fig. 1

a schematic, perspective view of a portion of a guide rail with a protection system according to the invention;

Fig. 2A

a schematic, perspective view of a portion of a guide rail with a protection system according to the invention, wherein a mechanical damage has occurred;

Fig. 2B

a schematic, perspective view of the guide rail shown in Figure 2A after the mechanical damage is cured.

Fig. 3A

a schematic, perspective view of a portion of a guide rail with a protection system according to the invention, wherein the corrosion protection film covers only the surface to be protected;

Fig. 3B

a schematic, perspective view of the guide rail shown in Fig. 3A after the anticorrosion film has been removed and thereby the surface to be protected has been exposed.

Detailed description

The invention relates to a method for temporarily protecting smooth surfaces which tend to corrode. The inventive approach will be described below with reference to a method example, wherein subsequently further methods are explained with reference to the first method example.

To illustrate the invention, reference is made to FIG. 1. It is a method for temporary protection of bare surfaces 11.1 against corrosion. The following steps are performed to provide a protection system that develops the desired protection.

After an optional cleaning step, a corrosion protection film 12 is applied to the exposed bare surface 11.1. In Fig. 1, the illustration was deliberately chosen so that the anti-corrosion film 12 is visible. In a further step, a self-healing, semi-solid protective layer 13 is applied. This protective layer 13 is applied so that it at least partially covers the anticorrosive film 12, as can be seen in Fig. 1. The anticorrosion film 12, together with the protective layer 13, forms an intelligent protection system, the structure and effect of which will be explained in later sections.

After the application of this protection system, the component, for example a guide rail 10, is protected against corrosion in the region of the smooth surface 11.1. The component can now be stored and transported as desired.

At a later time, for example, after transport to a construction site and on-site assembly, at least a portion of the bare surface 11.1 may be exposed again by peeling off at least a portion of the anti-corrosion film 12. The protective layer 13 can be easily combined with the Remove corrosion protection film 12. With a suitable choice of corrosion protection film 12, this neither a tool nor a special machine is required. The corrosion protection film 12 can be easily removed without residues.
A further method according to the invention is described below with reference also to FIGS. 3A and 3B. In the example shown, it is a guide rail 10, as used for example in elevator construction. The rail 10 has a T-shaped cross-section. The two opposite side surfaces of the web of the rail 10 serve as a guide for an elevator car or a counterweight. One of the two opposite side surfaces is designated 11.1 in FIG. 3A. The other side surface of the bridge is not visible. To ensure proper operation of the lift system, it is important that these side surfaces are bare. This means that these running surfaces 11.1 must have neither rust, nor residues of rust inhibitors nor mechanical damage. This is essential above all when it comes to emergency braking of the elevator car, since in this case braking means act directly on the running surfaces 11.1.

In the embodiment shown, the anticorrosive film 12 is applied only to those areas of the bare surface 11.1, which must later be exposed again. In FIG. 3A, it can be seen that the anticorrosion film 12 is strip-shaped and extends over the entire surface 11. 1 parallel to a longitudinal axis of the rail 10. The other surfaces of the rail 10 are not covered with the film 12. Now, the self-healing protective layer 13 is applied, this protective layer 13 then covering not only the anti-corrosion film 12 but also adjacent regions of the rail 10. In the example shown, the protective layer 13 covers all sides of the entire web of the T-shaped rail 10. The protective layer 13 extends into the right-angled transition area between the web and the transverse plate of the T-beam.

Upon exposure, only the strip-shaped anticorrosive film 12 together with a part of the protective layer 13 is removed, thereby exposing a bare surface 11.1, as shown in FIG. 3B. The self-healing protective layer 13.1 remains on the adjacent regions of the web, as can be seen from FIG. 3B.

This approach makes it possible to protect a component as a whole and to release a predetermined area if necessary. The shape of the predetermined area is defined by the shape of the anticorrosion film 12.

According to the invention, the protective layer 13 is characterized in that it is self-healing and forms a closed film. Furthermore, the anticorrosion film 12 and / or the protective layer 13 comprise hydrophobic constituents in order to prevent moisture from penetrating to the bare surface 11. 1 to be protected. In addition, the hydrophobic features cause water to be displaced.

In a preferred embodiment, the anticorrosion film 12 is characterized in that it builds up a strong adhesive bond to bare surfaces, in particular bare metallic surfaces. On the one hand, this leads to good adhesion of the anticorrosive film 12 to the bare surface and, on the other hand, this results in a blocking effect between the bare surface 11.1 and the anticorrosive film 12. This blocking effect can prevent the penetration of moisture.

In a preferred embodiment, the self-healing (self-balancing) protective layer 13 is particularly distinctive in that it forms a dense, closed film. As a result, the protective layer 13 forms a kind of closed membrane, which is preferably made moisture-repellent. The film preferably has a thickness of between 10 μm and 500 μm in order to achieve the desired protective effect.

The self-healing protective layer 13 preferably comprises a thixotropic agent to thereby form the dense, closed film during application, on the one hand, and to provide protection against damage by automatically closing the film after a local mechanical disturbance 13.1, as indicated in FIG. 2A. FIG. 2A shows a snapshot after the occurrence of a local mechanical disturbance 13.1. The disturbance may, for example, have been caused during transport of the component 10 by touching it with a tool or the like. In Fig. 2B, the same component 10 is shown a short time later. Due to the self-healing effect of the protective layer 13, the location of the disturbance 13.1 has automatically closed. This point is designated in FIG. 2B with 13.2. The closure of the disturbance 13.1 can take place, for example, by the protective layer 13 slowly flowing in and the open position closing again. Further details on the self-healing effect and the thixotropic agent used in this connection are given below.

In general, the term "thixotropic" refers to a reversible transition from a gel or galert-like state to a solid state. This transition is reversible. In the case of a thixotropic material, the viscosity is reduced when, for example, shear forces are applied.

The term "thixotropic" is understood below to mean the setting of the protective layer 13 in a plastic state with the addition of thickening agents, too Called thixotropic agent. In this state, the otherwise very liquid protective layer 13 can be adjusted so viscous that it can be processed easily on vertical components 10 and does not expire. The thixotropically-adjusted protective layer 13 has the property of being at rest like a gel and, when stirred or processed, like a viscous liquid. If there is a local disturbance, as indicated in FIG. 2A, the thixotropic agent reduces the viscosity in the region of the disturbance 13.1 and the protective layer 13 compensates for the disturbance, as shown in FIG. 2B.

• feuchtigkeitsabweisend,
• abriebsfest,
• niedrige Viskosität beim Aufbringen,
• schnelles Aushärten oder Abtrocknen,
• grifffest.

Particularly preferred is a self-healing protective layer (13) which combines one or more of the following functions in a substance or composition:

• moisture-resistant,
• abrasion resistant,
• low viscosity during application,
• rapid curing or drying,
• touch dry.

The present invention is based in a particular embodiment on a passivation of the surface to be protected 11.1. This results in an inhibition of corrosion. The protective film 12 and / or the protective layer 13 comprise a carrier material and one or more pH buffer components (buffering agents). These buffering contents are chosen to maintain the (metal) surface 11.1 to be protected near a pH where the surface is passive to corrosion. In order to protect a metal surface 11.1, the pH according to the invention is adjusted to a range between 8 and 13 pH. By adding the buffer components, the protection system of protective film 12 and protective layer 13 is basically adjusted.

Particular preference is given to protective films 12 and / or protective layers 13 which have corrosion-inhibiting constituents which are suitable for inhibiting the corrosion of the surface 11.1 in the presence of moisture or in the presence of other substances which promote corrosion.

In a particularly preferred embodiment, the anticorrosive ingredients coact with the buffering ingredients.

Particular preference is given to protective films 12 and / or protective layers 13 which have water-repellent (hydrophobic) components in order to prevent water from coming into contact with the surface 11.1. As hydrophobically acting components, for example, aluminum silicate and / or wax and / or oil can be used. Particularly suitable are synthetic oils and / or refined microcrystalline waxes.

It is also possible to add constituents to the protective film 12 and / or the protective layer 13 to provide effective protection against other corrosive materials such as air, carbon dioxide, chlorine ions, etc.

The protective system according to the invention comprising protective film 12 and protective layer 13 comprises one or more of the constituents mentioned.

The protective film 12 comprises a flexible carrier material which is suitable for receiving the buffers and / or other constituents. Particularly suitable as a film are: polymer material, polyacrylic, silicone, polyurethane, vinyl polymer, or polyvinyl acetate, to name a few examples.

The protective layer 13, however, has a special carrier component in order to give the protective layer 13 a film-like or gel-like consistency. Preferably, it is a waxy carrier component and forms a flexible, dense wax film after curing. After application or spraying, the thixotropic property of the protective layer 13 is used and acts against the ingress of moisture and / or liquid as described.

Preferably, said constituents are dispersed or deposited in the carrier material (in the case of the protective film 12) or carrier component (in the case of the protective layer 13).

According to the invention, an intelligent corrosion protection system is provided which, in contrast to the prior art, on the one hand offers good protection and on the other hand can be removed again without problems and effortlessly. The surfaces to be protected 11.1 are not only passivated if buffer constituents are used, or protected against ingress of moisture, if hydrophobic components are used, or reduces or prevents corrosion, if corrosion inhibiting components are used, but it becomes an effective overall protection which brings together the positive characteristics of multiple protective mechanisms in an unprecedented manner.

It is an advantage of the invention that the entire protection system is based on materials that are environmentally friendly. In addition, the application and removal is so executable that no chemicals must be used. There is also no increased energy consumption necessary because no hot air systems or grinding machines are needed.

The intelligent nature of the protection system according to the invention is realized by the combination of two protection means 12, 13. The protective film 12 acts inter alia as a water-repellent (hydrophobic) and / or waterproof barrier layer or intermediate barrier layer. If the protective layer 13 and the protective film 12 are injured, the components which are present in the protective layer 13 and / or the protective film 12 are used.

• Oberflächen von Führungen, insbesondere Führungen von Werkzeugmaschinen,
• Oberflächen von Antriebswellen,
• Oberflächen von Treibscheiben,
• Oberflächen von Messtischen, insbesondere Präzisionsmesstische.

The application of the inventive method is not limited to guide rails. The method can generally be applied to surfaces of components which are to be provided only temporarily with a corrosion protection, for example:

• Surfaces of guides, in particular guides of machine tools,
• Surfaces of drive shafts,
• Surfaces of traction sheaves,
• Surfaces of measuring tables, in particular precision measuring tables.

Claims (14)

Method for temporary protection of bare surfaces (11.1) against corrosion by the following steps: Applying a corrosion protection film (12) to a bare surface (11.1) to be protected, Applying a self-healing, semi-solid protective layer (13) which at least partially covers the anti-corrosion film (12), - later exposing at least a part of the bare surface (11.1) by peeling off at least part of the anticorrosion film (12) together with the protective layer (13) located on this part of the anticorrosion film (12), wherein the self-healing protective layer (13) forms a closed film and the anticorrosive film (12) and / or protective layer (13) comprise hydrophobic constituents to prevent moisture from penetrating to the bare surface (11.1) to be protected or existing moisture to displace. A method according to claim 1, characterized in that the corrosion protection film (12) by a strong adhesive bond to bare surfaces, in particular bare metallic surfaces, characterized, resulting in a barrier effect between the bare surface (11.1) and the anti-corrosion film (12). A method according to claim 1 or 2, characterized in that the self-healing protective layer (13) forms after application a dense, closed film, which preferably has a thickness between 10 .mu.m and 500 .mu.m. A method according to claim 3, characterized in that the self-healing protective layer (13) comprises a thixotropic agent and thereby forms, after the application of the protective layer (13), the dense, closed film which protects against damage by resisting local mechanical disturbance (13.1). closes automatically. Method according to one of claims 1 to 3, characterized in that the self-healing protective layer (13) combines one or more of the following functions in a substance: - moisture repellent, - abrasion resistant, low viscosity during application, rapid curing or drying, - good grip. Method according to one of claims 1 to 5, characterized in that prior to the application of the anti-corrosion film (12), a method is used to make the bare surface (11.1) dry, rust and grease-free. Method according to one of claims 1 to 4, characterized in that when applying the self-healing protective layer (13) is a brushing, rolling, or dipping method, or an airless spray method is used. Method according to one of claims 1 to 5, characterized in that the corrosion protection film (12) comprises oily and / or waxy constituents. Method according to one of claims 1 to 8, characterized in that the self-healing protective layer (13) comprises oily and / or waxy constituents, wherein the protective layer (13) preferably forms a wax film. Method according to one of Claims 1 to 9, characterized in that the bare surface (11.1) is the surface of a steel element (11). A method according to claim 10, characterized in that it is the steel element is a guide rail (11) for use in an elevator system, wherein the exposure during installation of the guide rail (11) takes place in the elevator installation or before commissioning of the elevator system. Method according to one of claims 1 to 11, characterized in that - When applying the anticorrosion film (12) only that area of the bare surface (11.1) is temporarily covered, which is to be exposed again during exposure, - The self-healing protective layer (13) covers not only the anti-corrosion film (12) but also adjacent areas, and - When exposing the self-healing protective layer (13.1) on the adjacent areas. A method according to claim 11, characterized in that the anticorrosive film (12) is designed as a strip which covers a running surface (11.1) of the guide rail (11) temporarily, after the removal of the anticorrosive film (12), the running surface (11.1) of the guide rail (11.1). 11). Component (10) with a surface to be protected against corrosion (11.1), characterized
that on the surface (11.1) a corrosion protection film (12) is applied and
in that a self-healing, semi-solid protective layer (13) which at least partially covers the anticorrosion film (12) is applied to the anticorrosion film (12),
wherein at least a part of the surface (11.1) can be exposed by peeling off at least part of the anticorrosion film (12) together with the protective layer (13) located on this part of the anticorrosive film (12),
wherein the self-healing protective layer (13) forms a closed film and the anticorrosion film (12) and / or protective layer (13) comprise hydrophobic components to prevent moisture from penetrating to the surface (11.1) or to displace existing moisture.

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