DE102009020264A1 - Method for painting a surface of a component - Google Patents

Abstract

The invention relates to a method for painting a surface of a component, wherein the surface has at least one painting area to be painted and at least one masking area not to be painted. In order to provide a method for painting a surface of at least one component, with which precise masking of the masking of the surface of a component in a practical manner and without much effort is possible compared to known solutions, the inventive method comprises the steps of: a) applying the Maskierbereichs with a cohesive, polymeric material in fine distribution to form a coherent polymer film; b) painting the painting area and c) removing the polymer film.

Description

The The invention relates to a method for painting a surface of a Component, the surface at least one Lackierbereich to be painted and at least one having not to be painted masking.

Of the Lackierbereich is referred to as such, because intended paint there is applied. The masking area is referred to as such because intended masking or no paint during the application is applied there.

Certain functional surfaces the surface of Components, in particular of plastic components, must be in usual Method by applying a Maskierbands, usually in the form of a special Adhesive film to be covered. Background is the necessary coverage or masking of these surfaces while a painting process, so that in these areas or on these surfaces later no paint film or spray located. Following the painting process usually takes place the removal of the preferably formed in the form of the adhesive film Maskierbands. Subsequently the further processing of these affected areas takes place various ready-made work (eg welding or sticking with other parts). The protection of these surfaces or Areas is imperative to ensure the function the subsequent operations.

This known masking method requires in particular with regard to on the paint of a large Number of components, in particular plastic bumpers for motor vehicles, a high personnel expenditure or high acquisition costs for suitable ones Automation solutions. Furthermore, as a result of the geometry of the component or of the component-dependent contours to be masked off, such as in the form of narrow radii, usually the need for denominations of the masking tape to be applied, along with the disadvantageous Circumstance that in the areas of denomination a desired overlap effect failed at subtracting and additional Effort required.

Of the Invention is therefore the object of a method for painting a surface specify at least one component, with respect to known solutions a precise one Masking the masking areas of the surface of a component to practical Way and without big Effort possible is.

• a) Beaufschlagen des Maskierbereichs mit einem kohäsiven, polymeren Material in feiner Verteilung, um einen zusammenhängenden Polymerfilm zu bilden;
• b) Lackieren des Lackierbereichs; und
• c) Entfernen des Polymerfilms.

To achieve this object, the method for painting a surface of a component according to claim 1 is provided. The method according to the invention for coating a surface of a component which has at least one painting area to be coated and at least one masking area which is not to be painted comprises the steps:

• a) finely distributing the masking region with a cohesive, polymeric material to form a coherent polymeric film;
• b) painting the painting area; and
• c) removing the polymer film.

Of the Step c) is preferably only after the complete curing of the Lacks executed.

The Formulation "not masking area to be painted " on the state after masking. Nevertheless, the component can in the masking area, a pre-varnishing already before applying the masking or contrasting paint, so that the masking in advance varnished surface protects, eg. against overpainting or against the thermal load of a paint drying oven. Under the Formulation "Apply of the masking region with a cohesive, polymeric material in finer Distribution "is an order of the polymeric material in discrete or separable Form, whether solid or liquid, whether in the form of droplets, Solid particles or the like, whether by knife coating, painting, spray on or similar. The polymeric material may be by hand or by means of an automated applicator on the masking area be applied. The application of the polymeric material in finer Distribution, in contrast to a masking band, allows a contour-conformant Masking. Due to the cohesive Properties can be applied in finely divided, polymeric Material to a coherent, one-piece and covering polymer film, preferably with training of chemical bonds to mask the masking area and to prevent a paint application in the masking area. The polymer film is preferably designed to be residue-free from the surface of the Component to be removed. The polymer film can then be residue-free and essentially in a single piece from the surface of the Component, preferably manually, removed or deducted. According to the invention, the surface may preferably have several Lackierbereiche which individually one after the other or to be painted at the same time.

It may prove helpful if the polymeric material is applied in the liquid state to the masking area. The liquid state of matter is characterized by a high volume resistance and low dimensional stability, so that the shape of the polymeric material, unlike solids by small forces that can be applied in particular manually NEN, is changeable. In this respect, the term "liquid" in particular also includes a viscous, z. B. gel-like consistency of the polymeric material. According to the invention, the liquid polymeric material can therefore be applied to the masking area in a practical manner, such as by knife coating, painting, coating or the like, preferably manually or preferably automated, depending on the location of the painting or the number of components to be painted can be done. In this case, the polymeric material preferably has a dynamic viscosity which, at the same temperature, is greater than the viscosity of water (water has a dynamic viscosity of about 1 mPa · s at normal pressure and a temperature of 20 ° C.) in order to prevent the water from flowing off already applied to the masking applied polymeric material. Preferably, at a temperature of 20 ° C, and preferably at normal pressure, the polymeric material has a dynamic viscosity greater than 100 mPa · s, preferably 10000 mPa · s. At a dynamic viscosity above 10000 mPa · s, which corresponds approximately to the dynamic viscosity of honey at a temperature of 20 ° C, the already applied polymeric material flows only very slowly due to possible inclinations formed on the surface of the component, so that during normal painting times, a substantially uniform form of the polymeric material applied to the surface is provided according to the invention. Particularly preferred is a polymeric material which, when mixed, ie under shear, has a viscosity lower than 20 Pa · s, preferably even lower than 10 Pa · s. With the release of the shear forces, the material forms a very high viscosity, so that overall the behavior can be described as thixotropic and it does not expire on vertical surfaces and remains stable in the applied form.

It can come in handy when the polymeric material is applied to the masking area as a spray becomes. The application as a spray allows a particularly conformal Order in hard-to-reach, curved Maskierbereichen. The polymeric material is preferably by means of a automated spraying device sprayed on the masking area. The automated spraying device is preferably attached to an industrial robot and has preferred an automated metering device on. By means of this practical rule Development in which the polymeric material is applied by spraying, can according to the invention provided an automation solution which are the inclusion of the method according to the invention in an automated painting process allows.

It Overall, it may prove convenient if the polymeric material is applied as a powder on the Maskierbereich. It can do this prove to be helpful if the component is electrostatically charged becomes. This can prevent the polymeric material Melted after application.

It can be cheap when the polymeric material has thixotropic properties. Of the Term of thixotropy denotes the property of a non-Newtonian Fluids, at a constant shear over a time axis to reduce the viscosity. After exposure to the shear stress, the initial viscosity is restored built up. Thus, the polymeric material can be adjusted so because of its thixotropic properties after application to solidify on the masking area. So is a contour right Order of the polymeric material possible without the applied Polymer material melts after application.

It may be helpful if the polymeric material is in a thickness of 50 to 500 μm, preferably 100 to 300 μm, preferably 200 μm, is applied. In this strength or thickness may be the polymeric material or the resulting Polymer film during withstand the stresses acting on the painting process. moreover the internal strength of the polymer film is sufficiently high, so that the polymer film without residue can be removed or deducted. The required strength or Thickness of the polymer film may vary depending on the selected polymer Materials vary.

It may be advantageous if the polymeric material is plastic, preferably on polypropylene, is adhesive. This allows injection molded components made of plastic, especially polypropylene, light and efficient be masked.

An advantageous method involves adjusting the cohesive and / or adhesive properties of the polymer film so that the cohesive forces of the polymer film are greater than the adhesion forces between the polymer film and the masking region. Thus, the formation of the polymer film according to the invention, with which residue-free removal from the surface of the component is possible, can be provided. In step (a), the smallest possible cohesive forces of the polymeric material are preferred, so that the polymeric material can be applied as finely as possible in a fine distribution. The adhesion forces should be so great that the applied polymeric material adheres to the masking area and does not flow off. Prior to or during step (b), cohesive forces and adhesion forces are preferred, such that the polymer film is e.g. B. during a washing process of the component ("power-wash"), in which the component is subjected to a water pressure of about 80 bar is not damaged, and does not detach. After step (b), the adhesion forces should be correspondingly small, so that the polymer film can be detached in one piece without residue and without much effort.

It can be useful be when the cohesive and / or the adhesive ones Properties of the polymer film set by energization of the polymer film become. The cohesive and / or the adhesive Properties of the polymer film are u. a. through the chemical Bindings influenced. The chemical bonds of the polymer film can turn for example about the energy supply, z. As irradiation can be influenced. For example the temperature influences the chemical bonds of the polymer film, z. B. in the networking.

It may prove practical when the polymer film is cured. As a cure In this context, the polymer film becomes an increase in the viscosity of the polymer film Understood. Change it the cohesion forces of the Polymer film and the adhesion forces between the polymer film and the masking region. By curing the polymer film increase the cohesion of the Polymer film and decrease the adhesion forces between the Polymer film and masking area. By energizing of the polymer film may be the cure cycle be matched to the painting cycle.

It may be helpful if the polymer film is chemically crosslinked. Through the networking, the cohesive forces of the polymer film and the adhesion forces between influence the polymer film and the masking region in opposite directions. With rising Degree of crosslinking increase the cohesion of the Polymer film and decrease the adhesion forces between the polymer film and the masking region. Solidified in the cross-linking the polymeric material shrinks slightly.

It may prove helpful when a degree of crosslinking of the polymer film at the end of the painting process 75%, preferably over 90%. At this degree of crosslinking the adhesion forces are correspondingly small, so that the polymer film in one piece without residue and without much effort supersede leaves.

It can be useful be when the crosslinking speed by energizing the Polymer film is controlled. This can be the networking cycle be matched to the painting cycle.

One preferred aspect of the invention relates to the use of a polymeric Material for masking a surface of a component in one Method according to one of the preceding embodiments, wherein that the polymeric Material preferably liquid Adhesive is preferably containing polyol and isocyanate. at The material used are preferably components of general polyurethane chemistry used, wherein at least one component, polyol or isocyanate, with a filler is formed, the total of the polymeric material thixotropic Lends properties. The preferred properties become special achieved well with a two-component polyurethane adhesive.

In a preferred embodiment is the polymeric material used to mask a surface of the component a material available under the trade name Araldit 2027. Araldit 2027 comprises the components XD 4712 (A) and XD 4713 (B), wherein XD 4712 (A) is the isocyanate component and XD 4713 (B) is the polyol component represents. The components XD 4712 (A) and XD 4713 (B) are preferably in a relationship mixed from 9.7 to 10 and are available as pastes with thixotropic properties in front. The viscosity is between 19,000 and 35,000 mPa · s.

The Component A containing isocyanate (XD 4712) preferably comprises about 55 to 65% by weight of modified diphenylmethane diisocyanate (MDI), about 33 to 44 wt .-% of inorganic fillers such as carbonates, wollastonite or silica, and about 0.5 to 2% by weight of water-absorbing additives.

The Component B containing polyol (XD 4713) preferably comprises a total of about 30 to 35 wt .-% Castor oil, about 9 to 13 wt .-% of polyols such as polyether polyols or aliphatic polyols, about 48 to 61 wt .-% inorganic fillers such as carbonates, wollastonite or silica, about 2 to 4 wt .-% water absorbent additives, about 0.2 to 1 wt .-% adhesion promoter (on Silane base), about 0.01 to 0.03 wt .-% catalysts such. Stannates or lithium chloride (LiCl), and lower components (about 0.1 to 0.2% by weight) of further additives.

The inventive method is particularly suitable for painting large-volume plastic components, such as spoilers, bumpers or Radlaufblenden. It is characterized by the fact that, in particular by application, doctoring or brushing of the polymeric material, a virtually completely contour-independent masking of masking regions is possible, wherein, in particular, even narrow radii can be easily masked on the plastic component. Therefore, the formation of a continuous, one-piece polymer film in highly curved areas is possible. This results in advantages when peeling off after painting, since the polymer film in a Remove piece. The technical and personnel effort in applying is reduced. Since the masking tape previously used is offered only in small rolls with short run lengths, resulting from the inventive method advantages, including the elimination of material residues on the rollers, the elimination of disruption or fallow times for role change and the elimination of any dependencies for recycling material.

Of the Masking area can have any geometry. Becomes a polymeric material with thixotropic properties may be used the masking area is also "overhead" since the polymeric material due to the thixotropic properties does not drip off. The masking area can, for example, band-shaped be formed, for example, unpainted surfaces for Gluing or welding to provide the component with other components. Typical widths of the masking area between 20 mm and 30 mm. In particular, the surface of the Component having a plurality of masking regions, wherein the Masking areas according to a predetermined patterns can be arranged relative to each other. Everyone Masking area of the plurality of masking areas may be, for example also band-shaped be formed, wherein the masking arranged in a line in a row one behind the other and can be spaced apart by Lackierbereiche. The individual masking areas can also punctiform, circular or oval-shaped be formed, with the individual masking rectilinear or along a curved Line can be arranged one behind the other.

Brief description of the drawings

1 shows a schematic representation of a plastic component in the form of a spoiler for motor vehicles, together with a schematic representation of an attached to an industrial robot applicator for the cohesive, polymeric material, eg. B. in the form of a spray device.

Detailed description of the preferred embodiment

following is an embodiment of Invention with reference to the attached Drawing closer explained.

This in 1 schematically illustrated plastic component in the form of a spoiler 10 for motor vehicles has a masking area in the form of an adhesive surface 12 on. In 1 is also schematically an industrial robot 18 shown, the straight along the longitudinal extent of the spoiler 10 is guided, with the spoiler 10 on a movable goods carrier (not shown) may be located.

At the industrial robot 18 is an automated applicator 16 for the cohesive, polymeric material 14 , z. In the form of a spraying device, which, inter alia, has an automatic or automated metering device (not shown in greater detail), and is arranged to cooperate with the industrial robot 18 predetermined areas of the surface of a plastic component, in this case in particular the adhesive surface 12 , with the cohesive, polymeric material 14 to apply in fine distribution, z. B. to spray them with the cohesive, polymeric material 14 to cover / coat. The spray device comprises a nozzle of appropriate geometry to apply the polymeric material in the desired thickness of preferably 200 μm and width (20-30 mm). To any areas of the surface of a plastic component with the cohesive, polymeric material 14 to cover / coat, has the applicator 16 a control device (not shown in detail), which is adapted to the applicator 16 in cooperation with the industrial robot 18 to control such that predetermined areas with the inventive cohesive, polymeric material 14 can be charged / sprayed. By means of this method according to the invention, a very high accuracy with regard to the attachment of the cohesive, polymeric material can be achieved. The cohesive polymeric material in the described embodiment is a liquid adhesive containing polyol and isocyanate, preferably Araldite 2027.

The process according to the invention initially involves the covering or coating of the adhesive surface 12 with the cohesive, polymeric material in fine distribution through the applicator 16 in cooperation with the industrial robot 18 , After curing of the cohesive, polymeric material 14 the painting of the surface of the spoiler takes place 10 , which also by means of the illustrated industrial robot 18 can take place, on which also a painting device (not shown in detail) can be attached. After painting the surface of the spoiler 10 and after a predetermined drying time for the applied paint, the removal of the cured polymer film, which is preferably carried out manually, takes place 14 from the adhesive surface 12 by suitable manual stripping.

The provided by the method according to the invention, unpainted remaining adhesive surface 12 is according to the invention a functional surface which can be glued in an advantageous manner with surfaces of other components or other plastic components or alternatively also welded, and in particular may have any geometry due to the practical spraying invention.

Overview the invention has the following advantages:

• • In feiner Verteilung aufgetragen werden und sich aufgrund seiner kohäsiven Eigenschaften zu einem zusammenhängenden, einstückigen Polymerfilm verbinden;
• • Automatisch aufgebracht werden;
• • Jeder Geometrie folgen, wie Rippen, Winkeln, etc;
• • Thixotope Eigenschaften aufweisen;
• • In flüssigem Aggregatszustand vorliegen und z. B. als Spray aufgetragen werden;
• • In festem Aggregatszustand vorliegen und z. B. als Pulver aufgetragen werden;
• • Auf dem Maskierbereich aushärten;
• • Auf dem Maskierbereich vernetzt werden;
• • Einen an den Lackierzyklus angepassten Vernetzungs- bzw. Härtezyklus haben, wobei die zur angestrebten Vernetzung bzw. Aushärtung erforderliche Zeit auf die zur Lackierung erforderliche Zeit abgestimmt ist, was z. B. durch dosierte und gezielte Energiebeaufschlagung erreicht wird; und
• • Auf Oberflächen kleben, selbst auf solchen mit geringer Oberflächenenergie wie Polypropylen.

The cohesive, polymeric material can:

• • are applied in a fine distribution and, due to its cohesive properties, combine to form a coherent, one-piece polymer film;
• • applied automatically;
• • Follow any geometry, such as ribs, angles, etc;
• • have thixotopic properties;
• • Are in liquid state and z. B. be applied as a spray;
• • exist in a fixed state of aggregation and z. B. be applied as a powder;
• • cure on the masking area;
• • be networked on the masking area;
• • Have an adapted to the painting cycle curing or curing cycle, wherein the time required for the desired cross-linking or curing is tuned to the time required for painting, which z. B. is achieved by metered and targeted energization; and
• • Stick to surfaces, even those with low surface energy such as polypropylene.

• • in Schritt (a) die Adhäsionskräfte zwischen dem Polymerfilm und dem Maskierbereich ausreichend groß sind, so dass das aufgetragene polymere Material im Maskierbereich haftet und nicht abfließt;
• • Vor bzw. während des Schrittes (b) die Kohäsionskräfte des Polymerfilms und die Adhäsionskräfte zwischen dem Polymerfilm und dem Maskierbereich ausreichend groß sind, so dass der Polymerfilm nicht beschädigt wird und sich während des „gesamten” Lackierprozesses (insbesondere während des sog. „power-wash”) nicht ablast;
• • In Schritt (c) die Adhäsionskräfte zwischen dem Polymerfilm und dem Maskierbereich möglichst klein sind, insbesondere geringer als eine innere Festigkeit des Bauteils, und die Kohäsionskräfte des Polymerfilms möglichst groß sind, so dass sich der Polymerfilm in einem Stück rückstandsfrei und ohne großen Kraftaufwand ablösen lässt.

The polymeric material or polymer film may have variable properties over time, e.g. B. is achieved by oxidation or by metered and / or targeted energization. The cohesive forces of the polymer film and the adhesion forces between the polymer film and the masking region are adjustable so that

• In step (a), the adhesive forces between the polymer film and the masking region are sufficiently great that the applied polymeric material adheres to the masking region and does not flow off;
• • Before or during step (b), the cohesive forces of the polymer film and the adhesion forces between the polymer film and the masking region are sufficiently great that the polymer film is not damaged and becomes damaged during the "entire" painting process (especially during the so-called "power -wash ") do not unload;
• In step (c), the adhesion forces between the polymer film and the masking region are as small as possible, in particular lower than an internal strength of the component, and the cohesion forces of the polymer film are as large as possible, so that the polymer film detach in one piece without residue and without great effort leaves.

Depending on the needed Curing / crosslinking time of the polymer film may, for. B. by means of a radiant lamp energy on the required area be applied, or the component can before the application of the heated polymeric material can be or the component with applied masking can then be heated. The curing / crosslinking is preferably carried out at a temperature of 20 to 80 ° C.

The Invention is applicable to packaging, cartons, components in the Industrial land transport, aviation technology, marine, for all fields of injection molded or laminated or molded parts with very low surface energy, where an exact template for the paint job is required.

Claims (15)

Process for painting a surface of a Component, the surface at least one Lackierbereich to be painted and at least one not having to be painted masking, characterized by the steps: a) applying the Maskierbereichs with a cohesive, polymeric material in fine distribution to a coherent To form polymer film; b) painting the painting area; and c) Remove the polymer film. Method according to claim 1, characterized in that that the polymeric material in the liquid state is applied to the masking area. Method according to one of the preceding claims, characterized characterized in that the polymeric material is sprayed onto the masking area is applied. Method according to one of the preceding claims, characterized characterized in that the polymeric material as a powder on the Maskierbereich is applied. Method according to one of the preceding claims, characterized characterized in that the polymeric material has thixotropic properties having. Method according to one of the preceding claims, characterized characterized in that the polymeric material is in a thickness of 50 to 500 μm, preferably 100 to 300 μm, preferably 200 μm, is applied. Method according to one of the preceding claims, characterized in that the polymeric material is based on plastic, preferably on polypropylene, adhesive is. Method according to one of the preceding claims, characterized by: adjusting the cohesive and / or the adhesive properties of the polymer film so that the cohesive forces of the poly Merfilms are greater than the adhesion forces between the polymer film and the Maskierbereich. Method according to one of the preceding claims, characterized characterized in that the cohesive and / or the adhesive Properties of the polymer film by energization of the polymer film be set. Method according to one of the preceding claims, characterized characterized in that the polymer film is cured. Method according to one of the preceding claims, characterized characterized in that the polymer film is chemically crosslinked. Method according to one of the preceding claims, characterized characterized in that a degree of crosslinking of the polymer film at the end of the painting process 75%, preferably over 90%. Method according to one of the preceding claims, characterized characterized in that the crosslinking rate by energization the polymer film is controlled. Use of a polymeric material for masking a surface a component in a method according to one of the preceding Claims, characterized in that the polymeric material is an adhesive is. Use according to claim 14, characterized that the polymeric material contains polyol and isocyanate.