DE102004047175A1 - Corrosion protection material applying method for vehicle body, involves inserting material into area of hollow space in vehicle body, moistening inner surface of space by material, and adhering material at inner surface in thin layer - Google Patents

Abstract

The method involves inserting a foamable corrosion protection material (2) into an area of a hollow space in a vehicle body. The vehicle body is subjected to conditions, in which a foaming of the material is caused by heating the body at an increased temperature level. An inner surface of the hollow space is moistened by the foamed material and the foamed material is adhered at the inner surface in a thin layer. Independent claims are also included for the following: (A) a foamable corrosion protection material applied into a hollow space (B) a vehicle comprising a vehicle body.

Description

The The invention relates to a method for the application of corrosion protection materials in cavities, in particular in cavities of vehicle bodies. Furthermore, the invention relates to a foamable Corrosion protection material. Furthermore The invention relates to a vehicle with at least one component from a prone to corrosion Material having at least one cavity, wherein the cavity provided with a corrosion protection material

typically, the application of corrosion protection materials in cavities, e.g. in the manufacture of vehicle bodies, by the spraying of Grow or the like by means of a spray lance in the cavities especially for it left or provided as a water drainage openings. Such manual or (partially) automated feasible production steps always very expensive and prone to failure. she need furthermore, time and space in the usual Manufacturing processes. In addition, points a spray job the disadvantage that e.g. due to undercuts, reinforcing ribs or the like in the spray shadow the spray lance lying areas not or not completely with the corrosion protection material be provided.

From the EP 0 003 223 B2 a method is known in which the preservation of the cavities by means of a corrosion protection material by flooding the entire cavities with the heated or molten material. In this case, a considerable effort in terms of plant technology is also necessary because, for example, in the case of vehicle bodies for each body, a special suitable manufacturing device for cavity preservation must be provided, and because it large amounts of liquefied with high energy costs wax or the like are always in circulation and constantly have to be supplemented and prepared in terms of quantity. Again, specially designed openings in the cavity are necessary.

the across from it is the object of the present invention, a corrosion protection for cavities, in particular for cavities of Vehicle bodies, to create, which is very easy and fast can be attached, and what a reliable, safe and long-term Corrosion protection possible.

According to the invention this Task by a method with the in the characterizing part of Claim 1 mentioned features. Likewise the task becomes through a foamable Corrosion protection material according to the claim 8 solved. By a vehicle having the features of the characterizing part of Claim 20 will be another solution given the above task.

The inventive method according to claim 1 allows the simple and safe introduction of the corrosion protection material into the cavity before it is made. The foamable corrosion protection material This is done on at least a portion of the base material, which later a part of the surface of the cavity is applied. After the cavity emerged is, can then immediately or at any later time the body having the cavity Be exposed to conditions which foam the foamable Corrosion protection material cause. Due to the volume expansion in the foam fill that frothed Corrosion protection material from the entire cavity. The corrosion protection components of the foamable Corrosion protection material so wet the inner surface of the Cavity. They also stick to this surface when the volume expansion effecting share of the foamable Corrosion protection material collapses again.

With the method according to the invention let yourself so easy and safe a very good corrosion protection in all, especially in non-or very poorly accessible cavities achieve.

The inventive method can preferably, for example, for the corrosion protection of cavities in Fahrzugkarosserien be used, since in particular here a safer and more reliable Corrosion protection for a good functionality the vehicles over is crucial for a long period of time.

According to a particularly favorable embodiment of the method according to the invention, the conditions which cause a foaming of the foamable corrosion protection material by an up heating the body having the cavity to an elevated temperature level.

Consequently can with volume expandable thermally expandable Proportions of the foamable Corrosion protection material very easy and efficient activation the corrosion protection of the cavity can be achieved by heating.

at the preferred field of application of the method according to the invention for corrosion protection of cavities In vehicle bodies, the finished body is heated anyway during thermal drying or curing, the so-called burn-in, the lacquer layers, e.g. the cathodically dip-coated basecoat. Without further production step and without temporal and energetic Effort can be achieved so the corrosion protection of the cavities.

The characterized by claim 8 corrosion protection material with his Composition of an anti-corrosion material and / or a Binder and a at temperatures above a starting temperature a strong volume expansion causing foaming auxiliary mixture, allows it cavities in which such a material is introduced by simple heating once over the above starting temperature also durable against corrosion to protect.

Next the foaming auxiliary mixture can while known against corrosion protective materials, which simultaneously are binders, e.g. Waxes with corrosion inhibitors if necessary, or protective against corrosion Materials and binders, e.g. lacquer-like materials with anti-corrosion inhibitors, be used.

The Vehicle according to claim 20 has at least one cavity, which in the manner set out above and / or with one set forth above expandable Corrosion protection material is protected against corrosion.

In a particularly favorable Embodiment of the invention is the corresponding cavity of the vehicle Completely closed trained.

In order to can additionally to prevent corrosion, the ingress of moisture is avoided which further minimizes both the susceptibility to corrosion and also the strength is increased. In conventional methods according to the In contrast, state of the art always requires openings in the cavities, around the corrosion protection material at all to get into this.

Further applies to the embodiments of the invention according to claims 8 and 20 and their developments the above already outlined in the context of the method according to the invention.

Further advantageous embodiments of the invention will become apparent from the further subclaims as well from the partially described below with reference to the drawing Embodiments.

there demonstrate:

1 a sheet metal component with a foamable corrosion protection material according to the invention, before its foaming;

2 the sheet metal part 1 which is joined with another component to a body having a cavity;

3 the body out 2 which is exposed to conditions causing foaming of the foamable corrosion protection material; and

4 the body out 2 , after carrying out the method according to the invention.

1 shows a schematic representation of a component 1 , For example, a preformed sheet metal component, which may later form the part of a longitudinal member in a vehicle body. The component 1 is with a foamable corrosion protection material 2 Mistake. This foamable corrosion protection material 2 can by means of a spray application or in the form of prefabricated mats or the like on the component 1 be applied. In the exemplary application for vehicle bodies, the corrosion protection material 2 preferably come as a band-like single-sided adhesive material of roles. On the component 1 can so one or more strips of suitable length - similar to an adhesive tape - are glued into the area, which later, possibly together with another component 3 , to a part of the inner surface 4 a cavity 5 will, as in 2 is apparent.

The foamable corrosion protection material 2 consists essentially of anti-corrosion material and / or a binder and a strong volume expansion causing frothing aid, detailed possibilities of its composition will be explained later in detail.

The one from the two components 1 . 3 resulting bodies 6 with the cavity 5 can then immediately after or at any later time of manufacture, be exposed to conditions which cause foaming of the foamable corrosion protection material 2 cause. The corrosion protection material 2 It experiences a volume expansion by typically several 100%, as in 3 is indicated by way of example. The entire cavity 5 is then from the now foamed corrosion protection material 2a filled. The corrosion-protecting materials and the binder adhere to the inner surface 4 of the cavity 5 and there form a closed layer of the corrosion protection material or a corrosion protection layer 2 B , So can a secure sealing of the inner surface 4 of cavities 5 against corrosion, even if they have no connection to the exterior of the finished body 6 have, so are completely closed in itself. However, the method can also be used wisely in other non-self-contained cavities, especially if these on the finished body 6 are difficult to access.

The foaming can preferably be effected by a thermal "starting" of the foaming auxiliary mixture, for example by heating above a predetermined starting temperature of about 80-150 ° C. After the body has been heated to such a temperature, for example by heating it for a few minutes is exposed to slightly higher ambient temperature of eg 150 to 170 ° C, the foaming of the foaming auxiliary mixture starts in the foamable corrosion protection material 2 which then undergoes volume expansion by several hundred.

Alternatively, it would be conceivable to start the foaming medium rays or waves (X-ray, ultra-sound) or the like. Which suitable starter substances activate and / or the foamable corrosion protection material 2 or its surroundings could heat up.

In the preferred use in vehicle bodies foaming of the foamable corrosion protection material 2 to the foamed corrosion protection material 2 B For example, during the thermal drying or curing, the so-called baking, one of the paint layers, for example, the cathodically dip-coated basecoat done. This can be a closed corrosion protection layer 2 B be achieved in the cavities, for which only in the shell in the manufacture of the body, the foamable corrosion protection material 2 in the area of the later cavity 5 must be inserted or applied. Further elaborate and ergonomic work steps that are very stressful for the workers performing them (eg hot wax, solvent fumes, overhead work, etc.) for the corrosion protection of cavities 5 in the Karoserie can be saved. Through the synergetic use of the "burn-in" for drying or hardening of paint and for simultaneous foaming of the foamable corrosion protection material 2 Furthermore energy, time and work space can be saved.

The foaming auxiliary mixture will typically completely or at least partially collapse after the body has cooled, as shown in FIG 4 is shown. However, the anti-corrosive material provided with the binder is still used as a corrosion protection layer 2c on the inner surface 4 of the cavity 5 attach and continue a closed corrosion protection layer 2 B form. The formation of the layer can be achieved by wetting additives in the corrosion protection material 2 be further improved. When using a paint-like binder this is together with any corrosion inhibitors on the surface 4 attach and harden there. Even with the use of wax as a corrosion-protective material, there is an adhesion of the cooling wax in the area of the surface 4 , This creates a closed permanent corrosion protection layer in every case 2 B on the inner surface 4 of the cavity 5 ,

Some compositions for possible solvent-containing and solvent-free binders with frothing auxiliary mixture are described below. These can also be known corrosion inhibitors, for example based on phosphates, carboxylic acid salts or the like, are added, which anodic, cathodic and / or with a buffering effectiveness in a given pH range corrosion inhibiting we ken. Further, a temporary anticorrosive effect also emanates from the closed layer of the varnish-type binder or wax which forms the surface 4 opposite the cavity 5 sealed.

All foamable corrosion protection materials described below by way of example 2 contain as frothing auxiliary mixture so-called hollow microspheres or microbeads. Such Mikroholkugeln typically contain a sheath of a polymeric material which encloses a propellant. In particular, the experiments carried out hollow microspheres or Mirkoperlen the F-series of the supplier Lehmann & Voss & Co. for use. These have a coat of a vinyl chloride / acrylonitrile copolymer. As a propellant you contain hydrocarbons, such as iso-butane. The basic feasibility of foaming was already found from a weight fraction of the hollow microspheres of 15 to 70% of the total foamable corrosion protection material. Mediocre to good results in terms of foaming and the corrosion protection to be achieved on the inner surface 4 25 to 50% by weight of hollow microspheres were obtained, very good results were achieved between 30 and 38, preferably between 33.3 and 33.7% by weight of hollow microspheres in the total foamable corrosion protection material.

Example 1 - Foamable Corrosion protection material based on waxy materials

Example 1 describes a waxy foamable corrosion protection material 2 , In addition to the above-mentioned proportion of foaming aids, a corrosion protection wax is used, for example a corrosion protection wax from the manufacturer Pfinder. This "pfinder wax" was added along with about 33 to 34% by weight of hollow microspheres per 100% by weight of foamable corrosion inhibiting material produced at ambient temperatures of the cavity 5 having body 6 of over 150 ° C and a holding time of about 15 minutes at this temperature, very good results were achieved. The percent volume expansion of the foamed anticorrosive material 2a opposite the foamable but still unfoamed corrosion protection material 2 was about 900 in these conditions.

The Subsequent Examples 2 to 4 only show the feasibility foaming in an exemplary proportion of in each case 33.30% by weight of Hollow microspheres. Possible Corrosion inhibitors and (further) additives are therefore in the following Examples not yet considered:

Example 2 - Foamable Corrosion protection material based on crosslinkable water-dilutable materials

The following table gives a possible recipe for a binder together with a foaming aid based on crosslinkable water-dilutable materials:

At ambient temperatures of the cavity 5 having body 6 from over 170 ° C and a holding time of about 30 minutes at this temperature were very good results in terms of foaming and to be achieved corrosion protection on the inner surface 4 achieved. The percent volume expansion of the foamed anticorrosive material 2a opposite the foamable but still unfoamed corrosion protection material 2 was about 800 in these conditions.

Example 3 - Foamable Corrosion protection material based on crosslinkable solvent-containing materials

The following tables give two possible recipes for one binder and one foaming auxiliary on the basis of crosslinkable solvent-containing materials:

At ambient temperatures of the cavity 5 having body 6 of over 170 ° C and a holding time of about 30 minutes at this temperature were with both formulations very good results in terms of foaming and to be achieved corrosion protection on the inner surface 4 achieved. The percent volume expansion of the foamed anticorrosive material 2a opposite the foamable but still unfoamed corrosion protection material 2 was about 800% under these conditions.

Example 4 - Foamable Corrosion protection material based on crosslinkable solvent-free materials

The following table gives a possible recipe for a binder together with a foaming aid based on crosslinkable solvent-free materials:

Claims (21)

Method for the application of corrosion protection materials in cavities, in particular in cavities of vehicle bodies, characterized in that a foamable corrosion protection material ( 2 ) before the production of the cavity ( 5 ) in the region of the cavity ( 5 ), later the cavity ( 5 ) having bodies ( 6 ) Is exposed to conditions which cause foaming of the foamable corrosion protection material ( 2 ), wherein the foamed corrosion protection material ( 2a ) the inner surface ( 4 ) of the cavity ( 5 ) and at this at least in a thin layer ( 2 B ). A method according to claim 1, characterized in that the conditions which a foaming of the foamable corrosion protection material ( 2 ), by heating the cavity ( 5 ) having body ( 6 ) are created to an elevated temperature level. A method according to claim 2, characterized in that to create the conditions which a foaming of the foamable corrosion protection material ( 2 ), the temperature of the body ( 6 ) is increased to at least 80 ° C, preferably to at least 120 ° C, more preferably to at least 150 ° C, is increased. Method according to one of claims 1, 2 or 3, characterized in that as foamable corrosion protection material ( 2 ) a material based on wax is used. Method according to one of claims 1, 2 or 3, characterized in that as foamable corrosion protection material ( 2 ) a paint-like crosslinkable material, which is dilutable by water or solvent, is used. Method according to claim 5, characterized in that that the paint-like cross-linkable material is solvent-free. Method according to one of claims 1 to 6, characterized in that the foamable corrosion protection material ( 2 ) Microballoons in a proportion of 15 to 70% by weight, preferably 25 to 50% by weight, particularly preferably 30 to 38% by weight. expandable Anticorrosive material, having an anti-corrosion Material; and / or a binder; characterized by a at Temperatures above a startup temperature a strong volume expansion causing foaming auxiliary mixture. expandable Corrosion protection material according to claim 8, characterized in that that the starting temperature at over 80 ° C, preferably above 100 ° C, especially preferably over 150 ° C, lies. expandable Corrosion protection material according to claim 8 or 9, characterized that protects against corrosion Material contains a wax. expandable Corrosion protection material according to claim 8 or 9, characterized that protects against corrosion Material contains a paint-like crosslinkable material. expandable Corrosion protection material according to claim 11, characterized in that that paint-like crosslinkable material contains isocyanate. expandable Corrosion protection material according to claim 11 or 12, characterized that paint-like crosslinkable material contains polyacrylate. expandable Corrosion protection material according to one of claims 8 to 13, characterized in that the protective against corrosion Material contains anodic and / or cathodic corrosion inhibitors. expandable Corrosion protection material according to one of claims 8 to 14, characterized in that the protective against corrosion Contains material corrosion inhibitors with buffering activity against relevant pH ranges. expandable Corrosion protection material according to one of claims 8 to 15, characterized in that the foaming auxiliary mixture Contains hollow microspheres. expandable Corrosion protection material according to claim 16, characterized in that that the hollow microspheres a sheath of a polymeric material have, which encloses a propellant. expandable Corrosion protection material according to claim 17, characterized in that that the propellant contains a hydrocarbon. expandable Corrosion protection material according to one of Claims 16 to 18, characterized that it has a proportion of microballoon balls of 15 to 70% by weight, preferably 25 to 50% by weight, particularly preferably 30 to 38% by weight, having. Vehicle having at least one component made of a material which is susceptible to corrosion and which has at least one cavity, the cavity being provided with a corrosion protection material, characterized in that the corrosion protection material has a continuous closed layer ( 2a ) by the foamable corrosion protection material ( 2 ) according to any one of claims 8 to 19 after foaming, which forms the inner surface ( 4 ) of the cavity ( 5 completely covered. Vehicle according to claim 20, characterized in that the cavity ( 5 ) is completely closed.