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EP 0 345 607 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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09.09.1992 Bulletin 1992/37 |
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Date of filing: 30.05.1989 |
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International Patent Classification (IPC)5: C23F 13/02 |
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Corrosion protection element for parts, particularly automotive parts, to be connected
by screws, bolts, etc.
Korrosionsschutzelement für Bauteile, insbesondere solche Bauteile für Kraftfahrzeuge,
die mittels Schrauben, Bolzen, etc. zu befestigen sind
Elément protecteur contre la corrosion pour pièces, notamment pour les pièces de voitures,
destinées à être fixées par des vis, boulons, etc.
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Designated Contracting States: |
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FR GB IT SE |
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Priority: |
08.06.1988 DE 3819495
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Date of publication of application: |
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13.12.1989 Bulletin 1989/50 |
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Proprietor: MINNESOTA MINING AND MANUFACTURING COMPANY |
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St. Paul,
Minnesota 55133-3427 (US) |
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Inventor: |
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- Scharpenack, Ralf A.
D-4040 Neuss (DE)
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Representative: Ruschke, Hans Edvard, Dipl.-Ing. et al |
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Ruschke Hartmann Becker
Pienzenauerstrasse 2 81679 München 81679 München (DE) |
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References cited: :
FR-A- 2 247 547 GB-A- 1 474 413
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FR-A- 2 418 279 US-A- 3 813 315
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The invention relates to a corrosion protection element for parts, particularly automotive
parts, to be connected by screws, bolts and the like and consisting at least in part
of metal, said corrosion protective element being adapted to be provided between said
parts at the juncture thereof and including zinc in layer form.
[0002] It is necessary frequently to provide for protection against corrosion between constructional
components that are to be connected to each other -- such as, in the automotive industry,
components that are to be attached to the chassis or to the body of a vehicle.
[0003] For obtaining optimum protection from corrosion, it has been known to provide a coat
of zinc on the entire body of a vehicle. On all of the vehicle body surface, this
coat of zinc will act as a cathode whenever corrosive processes take place. The provision
of a coat of zinc on the entire surface of a vehicle body is most costly, however.
In addition, problems arise when internally threaded bores must be provided on the
body for attaching components; such internally threaded bores will disrupt the zinc
coating. Even if such bores are provided on the body before the zinc coating is applied,
movements of the attached components relative to the body at the threaded bores will
again disrupt the zinc coating, giving rise to corrosive damage within a short period
of time.
[0004] It has been known furthermore to use a self-adhesive zinc foil as an element affording
protection from corrosion, such foil being provided at the juncture of rubber components
and steel components or between other metal attachments, for example; see Japanese
Patent JP-A-61-179,886. A zinc foil of this kind does not provide for a seal at the
juncture of the parts to be connected and is damaged rather easily by mechanical movements
of the parts between which it is located. As has been known, a satisfactory protection
of connected parts from corrosion will be obtained by the application of several layers
of paint; this again does not result in a seal between the parts to be connected.
Besides, the coats of paint will be damaged by mechanical movements of the parts connected.
[0005] Optimum protection from corrosion is obtainable where the parts to be connected are
high-grade steel, such as chrome-nickel steel. A suitable seal at the juncture between
the parts to be connected may be obtained by any sealing compound or sealing tape
which will accommodate slight mechnical movements. This kind of protection from corrosion
is very expensive, however.
[0006] Finally, there has been known a great number of sealing compounds which are not impaired
by relative movements of the parts to be connected. Compounds of this kind do not
afford any protection from corrosion, however.
[0007] It is the object underlying the invention to provide in a cost-effective manner a
corrosion protection element of the type specified above which provides an excellent
seal at the juncture of the parts to be joined, as well as optimum protection from
corrosion, regardless of relative movements of the parts connected to each other.
[0008] In accordance with the invention, this object is achieved by a laminate comprising
two high-purity zinc foils providing cathodic anticorrosive action, said foils being
disposed in a mutually overlying relationship and having therebetween a layer of an
elastic sealing material, said laminate conforming in an optimum manner to and sealing
the gap between the parts to be connected as these parts are being connected with
each other.
[0009] Preferred embodiments of the invention are defined by dependent claims 2 to 12.
[0010] It is preferred that the zinc foils be adhered to the layer of sealing material by
means of adhesive layers.
[0011] The laminate may have any desired geometric shape in plan view. It is preferred that
the laminate be manufactured in a continuous or strand form. The elastomer may be
a paste composition on the basis of polyisobutylene, (butyl) or polyurethane, for
instance, or may be present in the form of a closed-cell foam adhesive tape. The closed-cell
form adhesive tape may be acrylic foam or a neoprene or polyether tape, for example.
In the joining of the aforesaid parts such as the fixing of an attachment by means
of screws, it is important that the elastic adhesive sealing material exhibit excellent
conformability and strong adhesion for the desired sealing effect; in addition, it
should be a closed-cell material.
[0012] For use of the inventive corrosion protective element in the automotive industry,
it is of major importance that the laminate accept automotive body paints.
[0013] In a one-year long-term test of a test vehicle under corrosion promoting conditions
corresponding to a vehicle life of about ten years in a normal environment, the inventive
corrosion protection element was found not to be damaged or wear, and no corrosion
was found in the areas where attachments were connected. As a result, the inventive
corrosion protection element provides excellent protection from corrosion as well
as an excellent seal particularly between screwed-on attachments and the substrate,
such as fenders and the automobile body to which they are attached. The permanently
elastic adhesive layer of the laminate provides for easy application of the inventive
corrosion protection element in the vicinity of the bores provided in the attachments.
As the screws are tightened, the laminate will in an optimum manner conform to and
seal the gap between the parts to be joined, permanently sealing that gap. The zinc
provides for cathodic anticorrosive action in the gap and on the bore walls. As the
entire laminate is permanently elastic, it exhibits long life and stability against
aging despite relative movements between the joined parts. Because of its advantages
in the assembly process and the permanent anticorrosive effect, the inventive corrosion
protection element is most cost-effective. The adhesive-protecting liner protects
the permanently elastic self-adhesive layer from soiling before the laminate is put
to use. The inventive corrosion protection element has major advantages particularly
in the automotive, naval, and aircraft industries and for stationary installations
which require permanent stability in a humid environment.
[0014] The inventive corrosion protection element will now be explained in greater detail
under reference to the drawings.
Fig. 1 shows a schematic perspective view of the corrosion protection element;
Fig. 2 schematically shows the use of a corrosion protection element for fastening
a fender to a wheel case by means of threaded bolts;
Fig 3 shows another embodiment of the invention, used to protect the fastening bolts
of a bicycle stand.
[0015] As shown in Fig. 1, the corrosion protection element comprises a laminate 1 which
may be manufactured in a strand and has two spaced high-purity zinc foils 2 having
therebetween a layer 3 of an elastic adhesive sealing material engaging the facing
sides of foils 2. A layer 4 of a permanently elastic adhesive is provided on the opposite
side of lower zinc foil 2 (Fig. 1). In the storage condition of the corrosion protection
element, that layer 4 is covered by an adhesive-protecting liner 5 which may be stripped
away readily before use.
[0016] Fig. 2 shows the use of the corrosion protection element for fastening a fender 6
to the wheel case of a vehicle body 7. After bores 9 have been provided in the vehicle
body and in fender 6 to be attached, adhesive-protecting line 5 is stripped from laminate
1, and the latter is applied with the self-adhesive surface of layer 4 of permanently
elastic adhesive down on vehicle body 7 above bores 9 (in Fig. 2). Thereafter, fender
6 is fitted to the wheel case in vehicle body 7 and to the corrosion protection element
placed thereon, and threaded bolts 10 are introduced in bores 9 and tightened to secure
the fender to the wheelcase. As bolts 10 are tightened, laminate 1 of the corrosion
protection element conforms in an optimum manner to and permanently seals the juncture
11 between fender 6 and wheel case 7. High-purity zinc foils 2 of laminate 1 provide
cathodic anticorrosive action in area 11 and in bores 9. Because of the permanent
elasticity of the corrosion protection element, that element itself and the connection
between the joined vehicle parts show a long life and a high stability against aging
despite relative movements of fender 6 and the wheel case of vehicle body 7 during
vehicle operation. In particular, the self-adhesive coating of laminate 1 and the
deformability of layer 3 of an elastic adhesive sealing material provide for easy
assembly of the corrosion protection element and for easy installation of fender 6
on wheel case 7 of the vehicle body.
[0017] Fig 3 shows another example of the use of the element on a roofed bicycle stand,
which comprises supporting structure of steel beams 13 which is maintained in the
assembled condition by means of threaded bolt-and-nut fastener combinations 14 provided
adjacent sheet-metal roof sections 15. For protection from corrosion, the laminate
1 is provided above and below fastener combinations 14 to seal joint 16. In conventional
assemblies of this kind, corrosion will be caused by the slight but unavoidable relative
movements of the connected parts that are caused by wind and other mechanical forces
acting on the stand.
Example
[0018] A multi-layer construction consisting of the following materials including dimensional
data:
1. Corrosion protection element for parts to be connected by means of screws, solts and
the like and consisting at least partly of metal, said element including zinc in layer
form, characterized in that the element comprises a laminate (1) of two high-purity zinc foils (2) providing
cathodic anticorrosive action, said foils being disposed in a mutually overlying relationship
and having therebetween a layer (3) of an elastic sealing material.
2. Corrosion protection element according to claim 1, characterized in that the laminate (1) has a permanently elastic adhesive layer (4) provided on
a surface of one of the high-purity zinc foils (2) which faces away from layer (3).
3. Corrosion protection element according to claims 1 and 2, characterized in that in the storage condition, the adhesive layer (4) of laminate (1) is covered
by an adhesive-proctecting liner (5) and in that said laminate (1) is adapted to be
applied for self-adhesion in the area of fasteners (10, 14) by means of the adhesive
layer (4) to one of the members to be connected, such application being subsequent
to the removal of liner (5).
4. Corrosion protection element according to any one of claims 1 to 3, characterized in that the sealing material of the layer (3) is tacky.
5. Corrosion protection element according to any one of claims 1 to 4, characterized in that the laminate (1) is adapted to be manufactured in a strand form.
6. Corrosion protection element according to any one of claims 1 to 5, characterized in that the elastic adhesive sealing material (3) is a composition in paste form.
7. Corrosion protection element according to any one of claims 1 to 5, characterized in that the layer (3) of said elastic adhesive sealing material is formed of a closed-cell
foam adhesive tape.
8. Corrosion protection element according to claim 7, characterized in that the closed-cell foam adhesive tape (3) consists of acrylic foam.
9. Corrosion protection element according to claim 7, characterized in that the closed-cell foam adhesive tape (3) is a neoprene tape.
10. Corrosion protection element according to claim 7, characterized in that the closed-cell foam adhesive tape (3) is a polyether tape.
11. Corrosion protection element according to any one of the preceding claims, characterized in that the laminate (1) accepts body paint.
1. Korrosionsschutzelement für mittels Schrauben und dergleichen zu verbindende Teile,
von denen mindestens ein Teil aus Metall besteht, und das schichtmäßig Zink aufweist,
dadurch gekennzeichnet, daß es ein Laminat (1) aus zwei übereinander angeordneten Reinzinkfolien (2) mit
kathodischer antikorrosiver Wirkung aufweist, zwischen denen eine Schicht (3) eines
elastischen Dichtungsmaterials angeordnet ist.
2. Korrosionsschutzelement nach Anspruch 1, dadurch gekennzeichnet, daß das Laminat (1) eine dauerelastische Klebstoffschicht (4) aufweist, die auf
einer der zur Schicht (3) abgewandten Fläche einer der Reinzinkfolien (2) vorgesehen
ist.
3. Korrosionsschutzelement nach Anspruch 2 dadurch gekennzeichnet, daß die Klebstoffschicht (4) des Laminates (1) im Lagerzustand von einer Klebstoffschutzabdeckung
(5) abgedeckt ist, und daß nach Entfernen der Klebstoffschutzabdeckung (5) das Laminat
(1) mittels der Klebstoffschicht (4) selbstklebend auf einen der zu verbindenden Teile
im Bereich der Verbindungselemente (10, 14) aufbringbar ist.
4. Korrosionsschutzelement nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß das Dichtungsmaterial der Schicht (3) adhäsiv ist.
5. Korrosionsschutzelement nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß das Laminat (1) strangartig fertigbar ist.
6. Korrosionsschutzelement nach Anspruch 4 bis 5, dadurch gekennzeichnet, daß das Dichtungsmaterial der Schicht (3) eine pastöse Masse ist.
7. Korrosionsschutzelement nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die Schicht (3) von einem geschlossenzelligen Schaumstoffklebeband gebildet
ist.
8. Korrosionsschutzelement nach Anspruch 7, dadurch gekennzeichnet, daß das geschlossenzellige Schaumstoffklebeband aus Acrylschaum besteht.
9. Korrosionsschutzelement nach Anspruch 7, dadurch gekennzeichnet, daß das geschlossenzellige Schaumstoffklebeband aus Neopren besteht.
10. Korrosionsschutzelement nach Anspruch 8, dadurch gekennzeichnet, daß das geschlossenzellige Schaumstoffklebeband aus Polyether besteht.
11. Korrisionsschutzelement nach einem der vorgehenden Ansprüche, dadurch gekennzeichnet, daß es Körperfarben annimmt.
1. Elément protecteur contre la corrosion pour pièces à fixer à l'aide de vis, boulons
et autres moyens semblables, au moins en partie métalliques, cet élément comportant
du zinc sous forme de couche, caractérisé, en ce que cet élément comprend un stratifié (1) composé de deux feuilles de zinc
à très haut degré de pureté (2) pour assurer une protection cathodique contre la corrosion,
ces feuilles étant disposées l'une par rapport à l'autre de manière à se recouvrir
mutuellement, et ayant entre elles une couche de matériau d'étanchéité élastique (3).
2. Elément protecteur contre la corrosion selon la revendication 1, caractérisé en ce que la face qui n'est pas orientée vers la couche (3) de l'une des feuilles
de zinc à haut degré de pureté du stratifié (1) reçoit une couche adhésive indéfiniment
élastique (4).
3. Elément protecteur contre la corrosion selon les revendications 1 et 2, caractérisé en ce que, pendant la période de stockage, la couche adhésive (4) du stratifié (1)
est recouverte par une couche de protection de l'adhésif (5), et en ce que le stratifié
(1) est conçu pour être appliqué, par auto-adhésivité, à l'un des membres à fixer,
à l'aide de la couche adhésive (4), dans la zone des systèmes d'attache (10, 14),
en procédant à cette application après avoir ôté la couche (5).
4. Elément protecteur contre la corrosion selon l'une quelconque des revendications 1
à 3, caractérisé en ce que le matériau d'étanchéité de la couche (3) est collant.
5. Elément protecteur contre la corrosion selon l'une quelconque des revendications 1
à 4, caractérisé en ce que le stratifié (1) est conçu pour être fabriqué sous forme de cordon.
6. Elément protecteur contre la corrosion selon l'une quelconque des revendications 1
à 5, caractérisé en ce que le matériau d'étanchéité adhésif élastique (3) est une composition sous
forme de pâte.
7. Elément protecteur contre la corrosion selon l'une quelconque des revendications 1
à 5, caractérisé en ce que la couche (3) de ce matériau adhésif élastique est formée par une bande
adhésive en mousse à cellules fermées.
8. Elément protecteur contre la corrosion selon la revendication 7, caractérisé en ce que la bande adhésive en mousse à cellules fermées (3) est constituée par une
mousse acrylique.
9. Elément protecteur contre la corrosion selon la revendication 7, caractérisé en ce que la bande adhésive en mousse à cellules fermées (3) est une bande de néoprène.
10. Elément protecteur contre la corrosion selon la revendication 7, caractérisé en ce que la bande adhésive en mousse à cellules fermées (3) est une bande en polyéther.
11. Elément protecteur contre la corrosion selon l'une quelconque des revendications précédentes,
caractérisé en ce que le stratifié (1) accepte les mêmes peintures que la caisse du véhicule.