EP0514641A1 - Method for coating a fiber-reinforced plastic body - Google Patents

Abstract

For the application of a firmly adhering, resistant metallic or ceramic coating to bodies, consisting of reinforcing fibres and a synthetic-resin matrix, by a thermal spraying process or an electrochemical application process, a metal wire is wound around the body, the wire is firmly bonded to the surface of the fibre-reinforced body using synthetic resin, and the surface of the wound body thus obtained is machined in such a manner that exposed, clean, metallic surfaces are obtained, by means of which the coatings applied during thermal spraying or electrochemical application can be anchored by chemical bonds.

Description

The invention relates to a method for applying a firmly adhering, resistant covering consisting of at least one layer to the surface of a body which can be wrapped with a wire or a tape and which consists of a composite material made of fiber-reinforcing fibers and a plastic matrix.

By using fiber-reinforced plastics, considerable advantages can be achieved in machine, vehicle and plant construction. With good corrosion resistance, fiber-reinforced plastics are generally lighter than metals and, with the appropriate design, have at least equally good weight-related mechanical properties. These advantages fall with fast moving parts such as Shafts, rollers, rollers, tappets, levers or propellers etc. are particularly important.

Because of their large mass, high-speed rollers consisting of metals, for example for paper, film production and processing or printing machines, are exposed to considerable centrifugal forces, the inertia and thus the driving forces are comparatively large and high demands are made on the mass balance. For this purpose, rollers made of fiber-reinforced plastic, in particular carbon-fiber-reinforced plastic, are used today, which, with the same rigidity and improved dimensional stability, have a considerably smaller mass than rollers made of metal (DE-GM 83 22 639).

In plant and container construction, too, it is advantageous to use the high tensile and bending strength, the excellent torsional rigidity and the corrosion resistance of the fiber-reinforced plastics, which are lighter than metals or ceramic materials.

When used for conveying or transport processes or when exposed to substances moving relative to surfaces, however, the surfaces of fiber-reinforced plastics often prove to be insufficiently resistant. It has therefore been proposed to coat the surfaces with a resistant metal by galvanic application in order to reduce the appearance of abrasion and to avoid product contamination (DE-GM 84 06 019). In many cases, however, the quality of the layers applied in this way is unsatisfactory because of insufficient adhesive strength. According to another process (GB 887,366), moldings made of hardenable plastics such as formaldehyde resins are provided with coatings of metals or alloys by flame spraying, which are intended to make these parts resistant to impact and impact loads. According to the current state of the art, this process is cumbersome and complex, the adhesive strength of the layers is not sufficient, particularly with dynamic stress, to meet today's requirements and the choice of materials that can be sprayed on and combined is limited. In order to obtain enough firmly adhering layers, special conditions have to be observed. The material for the first layer cannot be chosen freely. Its melting point must be 400 ° C above the decomposition point of the plastic and its coefficient of thermal expansion must be greater than that of the plastic. It is also a condition that Material from which the second layer is to be built has a smaller coefficient of expansion than the previously applied first layer, which suggests poor adhesion of the first layer to its base. The plastic parts to be coated can contain fillers such as coke powder, graphite, wood flour, rock flour, quartz powder, paper or textile chips, which may possibly serve to lower the coefficient of thermal expansion. A participation of these fillers in anchoring the sprayed metals on the plastic surface is not indicated in the literature and is not possible because of the material differences between the filler and the layer materials.

Swiss patent specification 538 549 is also concerned with the application of protective layers to plastic parts made of synthetic resin, fillers and / or fibers by flame spraying. Thereafter, protective layers can be applied using the flame spraying method, but these layers have insufficient adhesive strength or irreparable damage occurs due to the process the surface of the carrier material, in particular the reinforcing fibers. To solve the problems, an intermediate layer of a fabric or braid and a synthetic resin is therefore first applied to the fiber-reinforced base body, which serves as a primer and buffer during flame spraying. The sprayed-on particles penetrate between the individual tissue pores and thus achieve a deep anchoring. This process, too, is technically unsatisfactory and, moreover, complex because the processing of the intermediate layer is only possible with substances which are accessible in the form of woven or braided fabrics of fabrics and braids requires expensive manual work or special technical facilities and the fabrics or braids have to be adapted exactly to the surface of the base body, which is particularly problematic in the case of self-contained surfaces due to the occurrence of bumps or overlaps. This fabric-containing layer serves as a thermal barrier during flame spraying. It is therefore subject to high internal stresses caused by differences in the thermal expansion coefficients between the synthetic resin matrix and the fabric material, which can lead to internal defects and delaminations in the lower body if the outer layer is sprayed on to a reasonably good degree. However, the adhesion of the sprayed-on layer also leaves something to be desired, despite improvements over the prior art, since in hot spraying the hot particles in all cases initially hit a surface made of synthetic resin, which more or less decomposes and, as tests have meanwhile shown, prevents a direct chemical connection of the sprayed material with the selected tissue or braid material.

Another method for coating carbon fiber reinforced plastic bodies with metals is described in the patent specification DE 35 27 912. Good adhesion of the protective layer is achieved here by using the plasma spraying process in conjunction with a C-fiber-reinforced substrate surface based on phenol formaldehyde resin. Although this process has found its way into industrial practice, the durability of layers produced by this process is also not entirely satisfactory. With strong mechanical loads such as cutting, grinding to the final dimension, under sudden loads or even for a long time operational delamination of the coating still occurs.

The invention was therefore based on the object of creating a method according to the preamble of claim 1, in which the choice of the matrix synthetic resin used and the choice of the substances suitable for a coating are not subject to any restrictions, the production of a coatable and a coated composite body is simple and layers with significantly improved adhesive strength can be produced.

The object is achieved by the characterizing features of claims 1 and 2.

• 1. Ein mit einem Draht oder einem Band umwickelbarer Grundkörper aus faserverstärktem Kunststoff, insbesondere eine Walze, Rolle oder ein Rohr ist mit mindestens einer Lage aus auf den Grundkörper gewickeltem Draht umgeben, wobei der Draht seinerseits von einem Kunstharz umgeben ist, das eine gute Haftung auf dem Draht und auf dem Grundkörper hat. Damit ist der Draht sehr gut auf dem Grundkörper verankert.
• 2. Die radial nach außen weisende Oberfläche der Kunstharz-Drahtschicht des umwickelten Grundkörpers wird mindestens so weit und in einer Weise abgetragen, daß einerseits an den Drähten in Richtung der späteren Beschichtung weisende, saubere Metalloberflächen entstehen, andererseits aber die Drähte weiterhin fest auf dem Grundkörper verankert bleiben.
• 3. Die auf diese Oberfläche mit Hilfe eines thermischen Spritzverfahrens oder auf galvanischem Wege aufgegebrachte erste Schicht findet ihre Verankerung an und in den freigelegten Oberflächenanteilen der aufgewickelten Drähte, die auf ihren nicht freigelegten Seiten fest über das Kunstharz mit dem Grundkörper verbunden sind. Die Verankerung der thermisch aufgespritzten oder galvanisch aufgebrachten Schicht wird durch eine chemische Bindung mit den über das Kunstharz auf dem Grundkörper verankerten Drähten bewirkt. Wesentlich für eine befriedigende Ausbildung einer solchen Bindung ist das Fehlen einer die nach außen weisenden Drahtoberflächen bedeckenden Kunstharzhaut. Versuche haben ergeben, daß auch die Haftung der thermisch aufgespritzten Schicht drastisch verschlechtert ist, wenn die heißen Partikel erst eine Kunstharzhaut durchschlagen müssen, ehe sie die Oberflächen der über das Kunstharz verankerten oder in das Kunstharz eingebetteten Drähte erreichen oder wenn sie gar nur mechanischen Halt in der Kunstharzschicht bekommen. Einer Haftung hinderlich sind auch thermische Zersetzungsprodukte, die beim Aufprall der heißen, geschmolzenen Beschichtungspartikel auf eine Kunstharzoberfläche entstehen. Im Gegensatz zu allen bisher bekannten Verfahren ist bei dem erfindungsgemäßen Verfahren eine Verankerung der thermisch aufgespritzten Schicht in der Kunstharzunterlage nicht mehr notwendig.

The following, interacting factors are essential for the invention:

• 1. A base body made of fiber-reinforced plastic, in particular a roller, roller or tube, which can be wrapped with a wire or a tape, is surrounded with at least one layer of wire wound on the base body, the wire itself being surrounded by a synthetic resin which has good adhesion on the wire and on the base. The wire is thus very well anchored to the base body.
• 2. The radially outward-facing surface of the synthetic resin wire layer of the wrapped base body is removed at least to such an extent and in such a way that, on the one hand, clean metal surfaces appearing on the wires in the direction of the subsequent coating, but on the other hand the wires continue to be firmly on the base body stay anchored.
• 3. The first layer applied to this surface by means of a thermal spraying process or by galvanic means is anchored to and in the exposed surface portions of the wound wires, which are firmly connected to the base body via the synthetic resin on their unexposed sides. The thermally sprayed or galvanically applied layer is anchored by a chemical bond with the wires anchored to the base body via the synthetic resin. Essential for a satisfactory formation of such a bond is the lack of a synthetic resin skin covering the outwardly facing wire surfaces. Experiments have shown that the adhesion of the thermally sprayed layer is drastically deteriorated if the hot particles first have to penetrate a synthetic resin skin before they reach the surfaces of the wires anchored or embedded in the synthetic resin or if they only have mechanical hold the synthetic resin layer. Thermal decomposition products that occur when the hot, molten coating particles impact on a synthetic resin surface also prevent adhesion. In contrast to all previously known methods, anchoring of the thermally sprayed-on layer in the synthetic resin base is no longer necessary in the method according to the invention.

The base body made of fiber-reinforced plastic is preferably a roller, roller or tube. However, the invention is not limited to these shapes, but extends to all bodies that can be wrapped with wire or tape.

Matrix material for the reinforcing fibers can be all synthetic resins from which bodies of the shape described above can be produced with sufficient shape and temperature stability. In particular, these are the thermosetting resins such as phenol formaldehyde, epoxy or polyester resins. But there are also thermoplastic resins such as Polypropylene, polyamides or polycarbonates are suitable. Glass fibers and aramid fibers are used primarily as reinforcing fibers, carbon fibers being intended to include graphite fibers in this term. Where it makes sense, other fibers, e.g. Mineral fibers such as basalt fibers or rock wool, metal fibers and carbide fibers such as SiC whiskers can be used. The fibers can be incorporated into the synthetic resin body as short cut or staple fibers, in the form of woven fabrics, braids, knitted fabrics or other textile structures of two or three dimensions or as continuous fibers.

The wire, which acts as an adhesion promoter for the thermally sprayed or galvanically deposited layer, is applied by winding. It is expedient to use one of the winding machines known in industrial practice, with which the winding density, ie the distance of the wires on the base body after winding, the wire tension and the winding angle can be adjusted. The synthetic resin with which the wire is anchored to the base body can be applied before or during the winding process. Before winding, it is applied either in a thin layer, for example using a brush, a spatula, or by spraying onto the cleaned, degreased and, if necessary, pre-machined basic body. The application during the winding is usually done by the wire itself, which acts as a carrier for the synthetic resin serves after being passed through a resin bath. The synthetic resin used can be the same as the matrix resin of the base body or another, which corresponds to the conditions of a good connection to the base body and good adhesion to the wire. In particular, phenol formaldehyde, epoxy and polyester resins and thermoplastic resins come into question here, the heat resistance of which is similar to that of the curable synthetic resins mentioned.

In most cases, the base body is processed by grinding or a machining process to obtain precise outer dimensions of the surfaces to be wound, so that layers of uniform thickness are present in the finished body, which is thermally sprayed or galvanically applied. This is particularly advantageous for achieving a uniform centrifugal force distribution with rotating bodies. If the dimensional stability of the various layers and / or the outer dimensions of the finished body are not subject to such high demands, the machining of the base body can be carried out less precisely or can be omitted.

Before the actual winding process begins, the wire is fastened to one side of the base body, for example by tying or clamping, so that a certain wire tension and precise guiding of the wire is ensured. In general, the wire is wound in such a way that adjacent wires practically touch one another in the wound state, ie that the distance at most corresponds to the thin synthetic resin skin adhering to them. The wires can also be wound up so that adjacent wires in the wound state have a certain distance, which should not exceed about 3 mm.

This embodiment is chosen if the body provided with the thermally applied layer should have a correspondingly structured surface. Diamond-shaped surface structures can be obtained, for example, if the wire has two layers at an angle, i.e. is wound with crossing wires. A single-layer wrapping layer is sufficient for the majority of applications. However, the invention is not limited to this embodiment. The wire can also be wound in several layers one above the other, in which case wires of different materials or different diameters can also be used.

The wire can be wound with a low or even a high pretension. The application of a high preload is e.g. then advantageous if, as in the case of rapidly rotating rollers, high demands are placed on the shaped body under dimensional stability under dynamic loading. The limit of the applied prestress is given on the one hand by thin wires by their inherent tensile strength and by strong wires by the hardness of the surface and the compressive strength of the base body. The wire used should have a diameter of at least 0.05 mm and at most 2.0 mm. Wire thicknesses of 0.1 to 0.2 mm are particularly preferred. For the purposes of the invention, the term wire also means narrow metal strips with a maximum width of 10 mm and a maximum thickness of 2 mm. Their use is advantageous if the largest possible metallic surface is to be available as a base for thermal coating.

With regard to the material composition, the wire used for winding corresponds to the metallic materials from which the thermally sprayed Layers can exist. Metals such as nickel, chromium, vanadium, manganese, iron, cobalt, titanium, silicon, aluminum, copper, zinc or alloys of one of these metals can be. Wires made of nickel, chrome, iron, aluminum, copper or zinc are used for galvanic coating.

It is generally advisable to clean the wires of surface contaminants, especially oils, greases or sizes, before they are used. In addition, to improve the adhesion of the synthetic resin to the wire, it is usually advantageous to use wires with roughened surfaces. Such roughening of the wire surfaces can be done in a known manner by etching, mechanical methods based on friction or by oxidation.

When designing the entire coating, a material is selected based on the requirements for the thermally sprayed layer, which results in a good bond with the material of the thermally sprayed layer and which can be well anchored to the base body as a wire via the synthetic resin provided. It is not a requirement that the wire anchored in the synthetic resin consists of the same material as the thermally sprayed layer.

After the winding process has ended, the wire is fixed to the base body again as at the beginning of the winding.

The finished wound body, if necessary or appropriate, is first freed of excess, surface-adhering resin by wiping or scraping, for example with a spatula, and then, optionally after wrapping with a release film, one Treatment applied to harden the applied resin. The curing conditions depend on the applied synthetic resin system and can be determined after a few preliminary tests based on the generally available instructions for use of the manufacturers.

After the synthetic resin has hardened, the body wrapped with wire is subjected to a further surface treatment. This process step is imperative for the success of the process according to the invention. It creates the prerequisite that a good chemical bond is achieved between the thermally sprayed or electrodeposited layer and the surfaces of the wire, through which the adhesion of this layer to the fiber-reinforced base body is mediated. The prerequisite for this is the removal of the synthetic resin skin initially covering the wire surfaces and the exposure of metallic contact surfaces. This is done by mechanical removal or by chemical dissolving or etching processes. In addition to the machining processes, grinding or sand or powder blasting are particularly advantageous as mechanical processes. If the wire surfaces obtained are too smooth, they can be roughened, for example, by etching with acids or alkalis. In the context of the invention, the term “chemical bond” is understood to mean all types of chemical bonds, such as ionogenic, covalent, metallic or coordinative bonds. During this processing, the proportion of the surface area of the metallic surfaces that is to be available for thermal spraying or galvanic application can be adjusted by the thickness of the removed layer. With only slight removal, ie if, based on the approximately circular cross-section of the wire, the imaginary secant marking the removal height is small in size, there are still considerable synthetic resin surface areas between the wire windings and the available metallic surface is comparatively small. If the removal of the imaginary secant becomes the diameter of the wire, the maximum possible metallic surface is available. With tightly wound wires, apart from the thin synthetic resin skins covering the wires, the entire surface is metallic. The latter state can also be achieved if the base body is wrapped with a metallic tape. A large metallic surface is also obtained when the wire is made of a metal that is very hard or tough compared to the hardened synthetic resin and the bare metallic surfaces are exposed by powder jets. In this case, the synthetic resin is blasted out of the gussets between the wire windings and the wire contours are essentially preserved. The user of the method sets the actually used surface portion according to the requirements of the coating task on the basis of preliminary tests.

If very high demands are made of the dimensional accuracy of the coated parts, it is advantageous to grind the surface of the roller blank to size and onto a smooth surface before coating the metal surfaces. The subsequently thermally sprayed on or galvanically deposited and possibly additionally applied layers then have a more uniform layer structure and a more uniform layer thickness and they can then be brought to the required surface quality and, if necessary, to the required dimensions with little effort.

At least one layer is sprayed onto the fiber-reinforced synthetic resin body, which has been prepared as described above, and is wrapped with metal wire, after cleaning from surface-adhering impurities such as dust or an oil film, using one of the thermal spray processes which are well known in the art. Flame spraying and plasma spraying, including the variant of vacuum plasma spraying, are particularly suitable as application methods. Which of the equally suitable methods is used depends on the circumstances of the user and the task.

• in Umfangsrichtung spiralförmig verlaufende, metallbeschichtete Stege, die durch zu ihnen parallel verlaufende, tiefer liegende, aus Kunstharz bestehende Strukturen getrennt sind,
• geschlossene metallische, beschichtete Oberflächen mit in Umfangsrichtung spiralförmig verlaufenden Erhebungen,
• metallbeschichtete geschlossene, glatte Oberflächen.

Entsprechende Oberflächenstrukturen können, in allerdings nicht so ausgeprägter Form auch beim thermischen Spritzbeschichten erhalten werden.The exposed metallic surface portions can also be the primer for galvanic coatings, which are otherwise produced by the generally known methods. Depending on the extent and structure of the bare metallic surface components, a large number of metallic surface structures can be generated by electroplating, some of which are described below by way of example:

• metal-coated webs running in the circumferential direction, which are separated by lower-lying structures made of synthetic resin that run parallel to them,
• closed metallic, coated surfaces with elevations spiraling in the circumferential direction,
• metal-coated closed, smooth surfaces.

Corresponding surface structures can also be obtained in thermal spray coating, although in a less pronounced form.

All materials which have been listed above as material for the wire winding layer can be used as spray material. They are metals such as nickel, chromium, vanadium, manganese, iron, cobalt, titanium, silicon, aluminum, copper, zinc or alloys of one of these metals. In addition, ceramic materials such as silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide or a combination of silicon carbide and silicon are used. The choice of the substance used depends on the intended use. The latter also defines the surface structure of the body and the post-treatment of the surface following thermal coating. Where only abrasion resistance matters or simple support or deflection functions such as with conveyor and roller belts, further processing is not necessary. For applications where dimensional accuracy and high surface quality are important, e.g. in the case of printing, inking, deflection or transport rollers in the manufacture of paper or films or processing, subsequent processing by machining processes, by grinding, polishing or lapping is necessary.

For some applications, it is necessary to manufacture bodies with a multi-layer covering on the base body containing synthetic resin. This can be the case, for example, if a ductile surface is required on the outside, which is supported or generalized on a hard, tough surface, if the applied base layer alone does not meet the intended use and the application of additional layers only provides the required properties of the coating Hardness, roughness, adhesiveness, porosity, electrical Conductivity, surface structure, etc. can be achieved. In these cases, it is possible to apply further layers to the first thermally sprayed-on layer using methods which are known per se and have been tried and tested in practice. This can be done by continuing the application with thermal spray processes or, if the base layer is electrically conductive, also by galvanic means. In this way, several layers can be applied one above the other, and the application method used can be changed from layer to layer. The materials applied in layers one above the other generally belong to different substances. But they can also be the same in terms of material.

• 1. aus der Wirkung stark unterschiedlicher thermischer Ausdehnungskoeffizienten zwischen dem faserverstärkten Kunstharzkörper und dem thermisch aufgespritzten Beschichtungsmaterial und
• 2. aus der Bildung von Zersetzungsprodukten des Kunstharzes während des thermischen Spritzens sowie
• 3. aus dem Entstehen eben solcher Zersetzungsprodukte beim thermischen Spritzen oder/und dem Vorhandensein einer Kunstharzzwischenschicht zwischen zusätzlich auf den faserverstärkten Kunstharzkörper aufgebrachten Schichten, die eine bessere Haftung der aufgespritzten Schichten bewirken sollten und der thermisch aufgespritzten Schicht

herrührten, sind für das thermische Aufspritzen der Schichten und für die Beanspruchung dieser Schichten im laufenden Betrieb praktisch bedeutungslos geworden. Die Unempfindlichkeit und die gute Haftfähigkeit der Beschichtung erkennt man daran, daß nach dem erfindungsgemäßen Verfahren beschichtete Körper ohne Abplatzen von Teilen der Schicht mit mechanischen Trennwerkzeugen geschnitten werden können und daß die Beschichtung Schlagbeanspruchungen beim Hantieren und im Betrieb ohne Beschädigungen gewachsen ist. Das Aufbringen und Präparieren der verfahrensnotwendigen, die verbesserte Haftfähigkeit bedingenden Schicht auf dem faserverstärkten Grundkörper kann mit geringem Aufwand unter Verwendung allgemein gebräuchlicher maschineller Einrichtungen wie Wickelmaschinen rationell ausgeführt werden. Eine Schädigung außenliegender Verstärkungsfasern durch auftreffende Partikel beim thermischen Spritzen kann ausgeschlossen werden. Der Anwender des Verfahrens ist in der Wahl der Harzmatrices für die Verstärkungsfasern und der Materialien für die aufzubringenden Schichten in weiten Grenzen frei.The advantages of the method according to the invention are obvious. Due to its variability, it can be easily adapted to a variety of technical problems. It is now possible to create surface coatings on fiber-reinforced synthetic resin bodies with little effort by means of a thermal spraying or galvanic application process with considerably improved adhesive strength and mechanical stability compared to the prior art. Up to now, the application of electrodeposited layers was only possible after a previous thermal spray coating with metals. The previously existing adhesion problems between the thermally sprayed layer and the fiber-reinforced synthetic resin body, the

• 1. from the effect of very different coefficients of thermal expansion between the fiber-reinforced synthetic resin body and the thermally sprayed coating material and
• 2. from the formation of decomposition products of the synthetic resin during thermal spraying as well
• 3. from the emergence of such decomposition products during thermal spraying and / or the presence of an intermediate synthetic resin layer between layers additionally applied to the fiber-reinforced synthetic resin body, which should bring about better adhesion of the sprayed-on layers and the thermally sprayed-on layer

originated, have become practically insignificant for the thermal spraying of the layers and for the stressing of these layers during operation. The insensitivity and the good adhesiveness of the coating can be recognized from the fact that bodies coated according to the method of the invention can be cut with mechanical separating tools without parts of the layer flaking off and that the coating has grown without any damage when handling and in operation. The application and preparation of the layer necessary for the process, which results in improved adhesion, on the fiber-reinforced base body can be carried out efficiently with little effort using generally used mechanical devices such as winding machines. Damage to the external reinforcement fibers from impinging particles during thermal spraying can be excluded. The user of the process is free to choose the resin matrices for the reinforcing fibers and the materials for the layers to be applied within wide limits.

• 1. Eine 2000 mm lange hohlzylindrische Walze mit einem Innendurchmesser von 90 mm aus mit Kohlenstoffendlosfasern verstärktem Phenolformaldehydharz, die durch Aufwickeln eines mit Phenolformaldehydharz getränkten Kohlenstoffadens auf einen zylinderförmigen Dorn in einer Vielzahl von Lagen, Aushärten des Harzes und Entformen hergestellt worden war, wurde auf einer Drehbank auf das Durchmesseraußenmaß von 100 mm zugeschliffen. Die so vorbereitete Walze wurde auf eine numerisch gesteuerte zweiachsige Wickelmaschine gespannt und zum Entfernen von störenden Oberflächenverunreinigungen mit ölnebelfreier Preßluft abgeblasen sowie mit Aceton entfettet. Danach wurde mit einem Pinsel ein Phenolformaldehydharz (Typ DW 247, Fa. Bakelite, mit 5% p-Toluolsulfonsäure als Härter, Viskosität 500 bis 1000 mPa · s) in dünner Schicht aufgetragen und zur Erzeugung einer gleichmäßig starken Schicht mit einer Ziehklinge abgezogen. Für den nun folgenden Wickelprozeß wurde ein Nickeldraht (98 % Nickel) mit einem Durchmesser von 0,2 mm verwendet. Dieser Draht wurde in einer Bohrung am äußersten Rand der Walze durch Verknoten fixiert und sodann mit einer Walzendrehzahl von 150 min⁻¹ bei einem Vorschub von 0,2 mm pro Walzenumdrehung unter einer Vorspannkraft von 6 N einlagig aufgewickelt. Am Ende des Wickelprozesses wurde der Draht mit einer Schraubklemme unter Fortbestehen der Spannkraft fixiert, die Walze aus der Wickelmaschine herausgenommen und das aufgebrachte Kunstharz bei Raumtemperatur 24 Stunden vorgehärtet. Das Endhärten erfolgte danach in einem Umlufttrockenschrank unter folgendem Temperaturprogramm:
  Aufheizen auf 120 °C, 2 Stunden,
  Halten auf 120 °C, 1 Stunde,
  Abkühlen auf Raumtemperatur ohne Zwangskühlung.
  Die Walze mit der aufgewickelten und durch ausgehärtetes Kunstharz auf ihrer Oberfläche fixierten Nickeldrahtschicht wurde auf einer Schleifmaschine mit Diamantscheibe um ca. 100 µm im Durchmesser abgeschliffen und ihre äußere Oberfläche durch Abblasen mit ölnebelfreier Preßluft entstaubt. Auf die so vorbereitete Mantelfläche der Walze wurde durch Plasmaspritzen unter Anwendung von auf diesem Gebiet der Technik üblichen Bedingungen eine Schicht aus einer Nickel/Chrom-Legierung (80 Gew.-% Nickel, 20 Gew.-% Chrom) aufgebracht. Nach der Spritzbehandlung wurden die Spitzen und Grate der aufgebrachten Beschichtung durch Bürsten mit einer Drahtbürste abgetragen und eine glatte Oberfläche erhalten.
• 2. Auf einer Wickelmaschine wurde auf einen Dorn von 90 mm Durchmesser ein durch ein Bad eines Epoxidharzes (Bakelite, L 20), Viskosität 800 bis 1000 mPa · s geleitetes Kohlenstoffasergroßkabel aus 40 000 Filamenten bis zu einer Schichtstärke von 10,3 mm gewickelt. Die Länge des Wickelkörpers betrug 2000 mm. Die Oberfläche des Wickelkörpers wurde mit einer Trennfolie umwickelt und der Körper in einem Umlufttrockenschrank mit folgendem Härtezyklus ausgehärtet:
  Aufheizen auf 80 °C, 1 Stunde,
  Haltezeit bei 80 °C, 10 Stunden,
  Aufheizen von 80 °C auf 130 °C, 1 Stunde,
  Haltezeit bei 130 °C, 10 Stunden,
  Abkühlen ohne Zwangskühlung.

The invention is illustrated by the following exemplary embodiments. However, it is not limited to the embodiments of the examples.

• 1. A 2000 mm long cylindrical cylindrical roller with an inner diameter of 90 mm made of phenolic formaldehyde resin reinforced with continuous carbon fibers, which was produced by winding a carbon thread impregnated with phenolic formaldehyde resin on a cylindrical mandrel in a plurality of layers, curing the resin and demolding, on one Grinded lathe to the outside diameter of 100 mm. The roller prepared in this way was tensioned on a numerically controlled two-axis winding machine and blown off with oil-mist-free compressed air to remove disturbing surface contaminations and degreased with acetone. Then a phenol formaldehyde resin (type DW 247, Bakelite, with 5% p-toluenesulfonic acid as hardener, viscosity 500 to 1000 mPa · s) was applied in a thin layer with a brush and removed with a scraper blade to produce a uniformly strong layer. A nickel wire (98% nickel) with a diameter of 0.2 mm was used for the subsequent winding process. This wire was fixed in a hole at the outermost edge of the roller by knotting and then wound at a roller speed of 150 min -1 with a feed of 0.2 mm per roller revolution under a pretensioning force of 6 N. At the end of the winding process, the wire was fixed with a screw clamp while the tension remained, the roller was removed from the winding machine and the applied resin was pre-hardened at room temperature for 24 hours. The final hardening then took place in a circulating air drying cabinet under the following temperature program:
  Heating to 120 ° C, 2 hours,
  Hold at 120 ° C, 1 hour,
  Cooling down to room temperature without forced cooling.
  The roller with the nickel wire layer wound on it and fixed on its surface by hardened synthetic resin was ground down on a grinding machine with a diamond disc by approx. 100 µm in diameter and its outer surface was dusted off by blowing with oil-mist-free compressed air. A layer of a nickel / chromium alloy (80% by weight of nickel, 20% by weight of chromium) was applied to the lateral surface of the roll thus prepared by plasma spraying using conditions customary in this field of technology. After the spray treatment, the tips and ridges of the applied coating were removed by brushing with a wire brush and a smooth surface was obtained.
• 2. On a winding machine, a carbon fiber large cable made of 40,000 filaments and wound to a layer thickness of 10.3 mm was wound through a bath of an epoxy resin (Bakelite, L 20), viscosity 800 to 1000 mPa · s, on a mandrel with a diameter of 90 mm. The length of the winding body was 2000 mm. The surface of the winding body was wrapped with a release film and the body was cured in a circulating air drying cabinet with the following hardening cycle:
  Heating to 80 ° C, 1 hour,
  Holding time at 80 ° C, 10 hours,
  Heating from 80 ° C to 130 ° C, 1 hour,
  Holding time at 130 ° C, 10 hours,
  Cooling down without forced cooling.

The roller thus obtained was then ground to a diameter of 99.9 mm on a grinding machine with a diamond grinding wheel. Thereafter, the roll for winding the wire into a numerically controlled two-axis, commonly used in industrial technology, Technically used numerically controlled biaxial winding machine equipped with a thread tensioning system clamped and its surface cleaned by blowing off with oil mist-free compressed air and degreasing by rubbing with acetone. A nickel wire, 98% nickel, diameter 0.2 mm was used for the coating. After setting the wire on the roll, which was done in the same manner as in Example 1, the wire was wound up under otherwise the same conditions as in Example 1, but with the difference that the wire in the winding apparatus after the thread tensioning arrangement was discharged through a bath Epoxy resin (Bakelite, L 20, viscosity 800 to 100 mPa · s) was pulled. The amount of synthetic resin taken up and carried away by the wire was sufficient to build up a synthetic resin wire layer that adhered well to the base body. After the winding body was completely covered with wire and the wire end was fixed on the roller, the body was again subjected to the same hardening treatment as described above in this exemplary embodiment. The roll was then ground on a grinding device with a diamond grinding wheel to a final dimension of 100.0 mm. After grinding, the roller was clamped for coating by the flame spraying method in a motor-driven rotating device, which made it possible to rotate about the longitudinal axis of the roller. Before the start of the spraying process, the surface of the roller was cleaned of adhering dust particles by means of compressed air free of oil mist. The outer surface of the roller was then coated with a 100 μm thick layer of an alloy with the composition 78% by weight of nickel, 15% by weight of chromium, 7% by weight of iron using the flame spraying process under conditions customary in this branch of technology. After coating, the roller surface was smoothed using a steel brush by removing the tips.

The thermally sprayed-on layers produced in the coatings according to Examples 1 and 2 were compared with layers of the same composition which had been produced without the use of an adhesion-promoting intermediate layer using thermal spray-coating processes according to the prior art. The test methods or types of stress used and the test results and observations obtained can be seen in the table overview.

It must be added to these observations and results that coatings, such as those made in Examples 1 and 2, but without first removing and cleaning the adhesive surfaces of the particles embedded in the synthetic resin intermediate layer from synthetic resin, only have adhesive strengths of the quality of the comparative example to reach example 1.

The results described clearly show the technical progress brought about by the invention.

Claims (17)

Method for applying a firmly adhering, resistant covering consisting of at least one layer to the surface of a body which can be wrapped with a wire or a tape and which consists of a composite material made of reinforcing fibers and a plastic matrix,
characterized in that - A metal wire is wound on the outer surface of the body which can be wrapped with a wire or a tape and fixed there with synthetic resin, which corresponds to the material used as the coating material or which is capable of chemically combining with the material serving as the coating material - The outer surface of the layer consisting of wound metal wire and synthetic resin is treated in such a way and to such an extent that synthetic resin-free, clean, metallic surfaces are produced which point in the direction of the subsequent thermal coating - And that the material for the production of at least the first layer of the covering by means of a thermal spraying process is sprayed onto the outer surface thus prepared of the layer consisting of wound metal wire and synthetic resin. Method according to the preamble of claim 1,
characterized in that - A metal wire is wound on the outer surface of the body that can be wrapped with a wire or a tape and fixed there with synthetic resin, which can serve as a base material for the galvanic deposition of at least one layer - The outer surface of the layer consisting of wound metal wire and synthetic resin is treated in such a way and to such an extent that synthetic resin-free, clean, metallic surfaces are produced which point in the direction of the subsequent galvanic coating - And that a layer from the group of metals nickel, chromium, copper, zinc is applied galvanically to the clean, synthetic resin-free surfaces. Method according to claims 1 and 2,
characterized in that
the wire is wound onto the body which can be wrapped with a wire or a tape in such a way that the wire windings coated with synthetic resin come into contact laterally. Method according to claims 1, 2 and 3,
characterized in that
the wire is wound onto the body that can be wrapped with wire or tape in one layer. Method according to claims 1, 2 and 3,
characterized in that
the wire is wound onto the body, which can be wrapped with a wire or a tape, in several layers one above the other. Method according to claims 1 to 5,
characterized in that
the wire is wound onto the body that can be wrapped with a wire or a tape under a pretension. Method according to claims 1 to 6,
characterized in that
the diameter of the wire is at least 0.05 mm and at most 2.0 mm. Method according to claims 1 to 6,
characterized in that
the diameter of the wire is at least 0.1 and at most 0.2 mm. Method according to claims 1 and 3 to 8,
characterized in that
the wire and the material used for the thermal spraying for applying the firmly adhering, resistant covering from one of the metals from the group consisting of nickel, chromium, vanadium, manganese, iron, cobalt, titanium, silicon, aluminum, copper, zinc, or from an alloy of one Metal consists of this group. Method according to claims 1 and 3 to 8,
characterized in that
the wire made from one of the metals from the group nickel, chromium, vanadium, manganese, iron, cobalt, titanium, silicon, aluminum, copper, zinc or from an alloy of a metal from this group and for thermal spraying to apply the adherent, resistant covering material used from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide or silicon carbide / silicon. Method according to claims 1 and 3 to 10,
characterized in that
the outer, firmly adhering, resistant covering is applied by flame spraying, Method according to claims 1 and 3 to 10,
characterized in that
the outer, firmly adhering, resistant covering is applied by plasma spraying. Method according to claims 1 and 3 to 12,
characterized in that
at least one further layer is thermally sprayed onto the first, thermally sprayed-on layer of the firmly adhering, resistant covering. Method according to claims 1 and 3 to 13,
characterized in that
one or more layers are / are electrodeposited onto at least one of the thermally sprayed-on layers, provided that it is electrically conductive. Method according to claims 1 to 14,
characterized in that
the body to be coated, which can be wrapped with a wire or a tape, has a matrix of phenol formaldehyde resin. Method according to claims 1 to 14,
characterized in that
the body to be coated, which can be wrapped with a wire or a tape, has a matrix of epoxy resin. Method according to claims 1 to 16,
characterized in that
the body to be coated, which can be wrapped with a wire or a tape, is reinforced with carbon fibers.