EP2914385B1 - Method for coating objects - Google Patents

Description

The invention relates to a method for coating objects, in particular vehicles and vehicle parts, to a film coating which can be peeled off or sprayed over again after use, and to a vehicle provided with a film coating.

State of the art

Vehicles are usually sprayed in several layers and colored. Coatings without spray processes are also known, in which coated films are applied to a substrate, for example to a motor vehicle body. The films can be provided on one side with one or more coating layers and can have an adhesive layer on the same or the other side, so that the film can be fixed on the substrate. The foils can be laminated onto the substrate so that they remain fixed on the substrate.

For example, a "process for producing color coatings" is known ( DE 603 04 093 T2 ), in which a color coating layer in the form of an outer coating layer is proposed. The coating layer is part of a multi-layer coating and comprises a thermosetting coating composition while avoiding the spray application. It has no separate adhesive layer and no carrier layer, such as a film.

The substrate, in particular provided with a precoat, is coated with the additional coating layer, which is applied from a thermosetting coating composition and thermoset.

This method has the disadvantage that the film is difficult to remove again. The range of colors in this process is limited and the gloss effect is often unsatisfactory.

Also known is a "lacquer system and method for producing film-like peelable, film-like coatings with uncrosslinked polymers" ( DE 41 10 135 A1 ). A sprayable coating system containing linear polymers is proposed. This is intended to provide vehicles with a weatherproof coating in order to protect them from corrosion and mechanical influences, but to be removable again after a period of time. For this purpose, polymers are used which are used for film coating using liquid or fat-like plasticizers of the alkyd resin type. The coating system is applied to the object to be coated and then the film-forming liquid film is dried to form a film with uncrosslinked, soluble polymers. This creates peelable films.

The JP 2000 070839 A discloses a "temporary coating of the color change technique". A releasable aqueous coating agent which forms a releasable film is formed using an emulsion coating material made of rubber, styrene, butadiene rubber, isoprene rubber, chloroprene rubber, nitrile-butadiene rubber, silicone rubber, fluororubber, urethane rubber, acrylic rubber, or a derivative thereof. to which a top coating material is applied which contains a color pigment and a metal pigment and has at least 50% spread rate of a formed film to form a releasable composite film.

The US 6 126 989 B1 shows a "urethane acrylic rubber coating and method for producing a vehicle bed interior paneling". A method for forming an elastic rubber-based coating is described. The first step in the process is to provide a water-curable liquid rubber and a water-based acrylic polymer. The rubber and the acrylic polymer are then combined to form a hardening rubber-acrylic composite. This curing rubber-acrylic composite is applied to the surface of a substrate and can be at a temperature in the range of 35 ° F. up to 110 ° F. fully cure to form a rubber-based coating.

The US 6,964,989 B1 shows a "peelable coating composition". This disclosure generally relates to water-resistant, peelable protective and decorative, clear or pigmented coating compositions, and more particularly to solvent and water-based polymeric coating compositions that form a protective and / or decorative coating on a variety of substrates, including automotive paints, metals , Plastics, concrete, natural and synthetic elastomers and ceramics.

The WO 2008/097415 A2 describes "peelable coating compositions". A composition for forming a peelable coating is disclosed, the composition comprising an aqueous carrier, a water dispersible polyvinyl butyral and an acrylic latex compound.

This coating does not produce a color effect similar to that of the usual color coating. The film has little adhesive force, so that it is only suitable for short-term use as a protective cover.

It is therefore an object of the invention to provide a method which enables objects to be coated with a greater variety of colors, matt and high gloss or even short-term color changes for vehicles or parts.

Disclosure of the invention

A method for coating objects, in particular vehicles and vehicle parts, a film coating that can be peeled off or sprayed over again after use, and a vehicle provided with the film coating are proposed.

The invention is defined by the appended claims.

The vehicle is sprayed to produce a film coating. A liquid rubber is used, which is applied to the vehicle in several layers. Layer by layer, a "rubber film" is built up, which in the finished state is indistinguishable from normal painting and can be removed completely and without residue. This process is suitable for application to the basecoat of the vehicle. This coating can be made transparent or combined with color pigments, so that matt or glossy transparent or colored coatings are achieved.

• Reinigung und Entfettung mit geeigneten Substanzen wie Silikonentferner oder Alkohol
• Ggf. Abkleben der nicht zu beschichtenden Teile

The following steps are carried out on the vehicle beforehand:

• Cleaning and degreasing with suitable substances such as silicone remover or alcohol
• Possibly. Mask the parts that are not to be coated

The ideal processing conditions are an air temperature of + 10 ° C or more and up to 75% relative humidity.

This is followed by one or more of the following process steps:

1st embodiment a) A first exemplary embodiment is explained using the following method steps:

• Liquid rubber is diluted at least 1: 1 with an acrylic thinner. The so-called "short" dilution (a few seconds to a few minutes) is advantageous, "long" dilution also works (several minutes). The proportion of dilution can also be increased in order to achieve an optimized viscosity. The dilution ratio must be matched to the air pressure: higher pressure - more dilution. A diluted acrylic paint can be added to achieve a colored film coating.
• The diluted liquid rubber is filled into a spray gun with a nozzle (for example with a nozzle size of 1.4-1.8) or into an electric sprayer through a sieve. Any nozzle size is conceivable for the nozzle size, the usual nozzle sizes are between 0.6 - 1.9 mm.
• The air pressure should be between a minimum of 2 bar and a maximum of 4 bar. The higher the pressure, the finer the liquid rubber is applied. At higher pressures, more dilution must be added so that no liquid rubber dries in the gun or in the air when spraying. This would form cobweb-like particles. If the dilution is too high, there is a risk that the material will run smoothly when applied
• The ready-to-spray material is applied to the surface. The first layer is applied relatively dry. All other layers are applied evenly wet. A sign of optimal application is that the wet surface resembles an orange peel
• Wait at least 10 minutes between the application of each layer, possibly even longer, until all dilution components have evaporated. This can be seen from the fact that the layer is "finger dry" or matt. There are between 2 and almost infinitely many, preferably between 4 and 7 layers to be applied, depending on how thick the finished film should be
• After the last shift, wait at least 30 minutes until it is dry.

After completing these steps of the method according to the invention, a transparent or colored film with a matt finish is achieved.

b) To produce a film with a high gloss, the following further steps of the method are carried out:

• Spray the film with a transparent plastic coupling agent and let it dry for at least 15 minutes [this process step is not absolutely necessary]
• Mixing clear varnish (e.g. 1 I) with 10% plasticizer (e.g. 100 ml) [this process step is also not absolutely necessary]. The clear coat is preferably a scratch-resistant 2K-HS clear coat based on reflow technology. This clear coat has a high resistance to micro scratches and chemicals. It is VOC compliant. Then the total amount in relation to the clear lacquer, usually 2: 1, is mixed with hardener. This total amount may be followed by up to 30% of a thinner, for example an acrylic thinner
• Spray this ready-to-use clear coat dry onto the film. Then apply one or two more wet coats. Wait at least 10 minutes between each shift. After the last layer, let the clear coat flash off for at least 15 minutes. Then it can be blow-dried and / or fired at around 80 degrees Celsius. Let it harden. After curing, the surface can be sanded and polished until the desired result is achieved.

After completing these further process steps, a transparent or colored film with a high-gloss finish is achieved.

2nd embodiment a) A further advantageous embodiment of the invention is described in this second embodiment:

• Dilute transparent liquid rubber at least 1: 1 with acrylic thinner. This is advantageously done with the so-called "short" dilution, a "long" also works. The proportion of dilution can also be increased to the to achieve optimal viscosity. Here it is important to adjust to the air pressure. A higher pressure requires more dilution.
• Mixing undiluted acrylic-based paint in a 1: 1 ratio with acrylic thinner or using ready-to-spray acrylic paint; Instead of acrylic lacquer, a single-layer lacquer based on acrylic can also be used. Mix the completely mixed, transparent liquid film in a ratio of min. 2: 1, max. 1: 1, with the diluted paint. To clarify the following calculation example:
  1l ready-to-use colored liquid film contains 700 ml of diluted transparent liquid rubber and 300 ml of diluted acrylic paint
• The diluted liquid rubber is filled into a spray gun (for example with a nozzle size of 1.4-1.8) or into an electric sprayer through a sieve
• The air pressure should be at least 2 bar and a maximum of 4 bar. The higher the pressure, the finer the liquid rubber is applied. At higher pressures, more thinner must be added so that no liquid rubber dries in the gun or in the air when spraying and that cobweb-like particles form. If the dilution is too high, there is a risk that the material will run smoothly when applied
• The ready-to-use colored material can either be applied directly to the surface or 1 - 2 layers of transparent "base film" applied beforehand; this is for greater durability. Apply the first layer relatively dry. Apply all other layers evenly wet. A sign of a perfect application is that the wet surface resembles an orange peel
  ∘ Wait at least 10 minutes between each shift, possibly longer, until all of the dilution has evaporated. This can be seen from the fact that the layer is "finger dry". Apply between 4 and 8 layers, depending on how thick the finished film should be and whether the desired color coverage has already been achieved
• After the last shift, wait at least 30 minutes until it is dry.

After completing these process steps , a colored film with a matt finish is obtained. All colors that can be produced on an acrylic basis are possible.

b) In a further exemplary embodiment, the following additional steps are carried out to achieve a colored film with a high-gloss finish:

• Spray the film with a transparent plastic bonding agent and let it dry for at least 15 minutes
• Mix clear coat (e.g. 1 I) with 10% plasticizer (e.g. 100 ml). Then the total amount in relation to the clear lacquer, usually 2: 1, is mixed with hardener. This total amount may be followed by up to 15% of a thinner, for example an acrylic thinner
• Spray this ready-to-use clear coat dry onto the film. Then apply two more wet coats. Wait at least 10 minutes between each shift. After the last layer, let the clear coat flash off for at least 15 minutes. Then it can be blow-dried and / or fired at around 80 degrees Celsius. Then the curing takes place.

After completing these process steps, a colored film in any desired color with a high-gloss finish is achieved.

3rd embodiment: a) The process steps for mixing and coating with transparent liquid film and the subsequent dyeing with water-based paint are explained:

• Dilute transparent liquid rubber at least 1: 1 with acrylic thinner. A "short" dilution is best, a "long" one also works. The proportion of dilution can also be increased to achieve the optimum viscosity. Here it is important to adjust to the air pressure. A higher pressure requires more dilution.
• Conventionally dilute water-based paint or use diluted water-based paint
• Pour the diluted liquid rubber into the spray gun (e.g. with nozzle size 1.4-1.8) or into an electric sprayer through a sieve
• The air pressure should be at least 2 bar and a maximum of 4 bar. The higher the pressure, the finer the liquid rubber is applied. At higher pressures, more dilution must be added so that no liquid rubber dries in the gun or in the air when spraying, and spider web-like particles form. If the dilution is too high, there is a risk that the material will run smoothly when applied
• Now apply the ready-to-use transparent or colored liquid film to the surface. Apply the first layer relatively dry. Apply all other layers evenly wet. A sign of optimal application is that the wet surface resembles an orange peel. Wait at least 10 minutes between each shift, possibly longer, until all of the dilution has evaporated. This can be seen from the fact that the layer is "finger dry". Apply between 4 and 7 layers, depending on how thick the finished film should be
• After the last shift, wait at least 30 minutes until it is dry
• Spray the film with plastic bonding agent and let it dry for at least 15 minutes
• Now the ready-to-use water-based or acrylic-based paint can be applied to the film, as with conventional painting. As soon as the desired coverage and color is achieved, let the film dry. The film can also be blow-dried or burned.
• Sealing the water-based paint by applying matt clear coat or a conventional clear coat. Depending on the selection, a matt or glossy finish is obtained (see process example 3b)

After the completion of these process steps, a transparent film, colored by the application of water-based paint with a matt finish, is formed. All colors that can be produced on a water basis can be achieved.

b) To form the film in high gloss, the following further process steps are carried out:

• Mix clear coat (e.g. 1 l) with 10% plasticizer (e.g. 100 ml). Then the total amount in relation to the clear lacquer, usually 2: 1, is mixed with hardener. This total amount may be followed by up to 15% of a thinner, for example an acrylic thinner
• Spray this ready-to-use clear coat dry onto the film. Then apply two more wet coats. Wait at least 10 minutes between each shift. After the last layer, clear coat min. Allow to dry for 15 minutes. Then it can be blow-dried and / or fired at approx. 80 degrees Celsius. Then the curing takes place.

After these process steps, a transparent film, colored by applying water lacquer, is achieved with a high-gloss finish.

4th embodiment:

As a further exemplary embodiment, the vehicle provided with the film coating according to the invention from the liquid rubber layers can additionally be sprayed with a single-layer paint. This allows the underlying film to be colored. However, a glossy or a matt single-layer lacquer can be applied.

As already described, the film is applied in several layers by spraying and drying, then the single-layer lacquer is applied to the film coating, in particular sprayed on. Depending on the addition or use of color or choice of single-layer lacquer (matt or glossy), the desired color and finish are obtained. This embodiment has the Advantage that the sealing is finished with the application of the one-coat lacquer, no further layer (clear lacquer) is necessary.

All of the exemplary embodiments can also be modified in an alternative embodiment, the application of the plastic bonding agent being omitted and a different clear lacquer being applied instead.

The clearcoat is designed so that it forms a connection with the film without a plastic adhesive. The clear coat is preferably a scratch-resistant 2K-HS acrylic clear coat based on reflow technology. This clear coat has a high resistance to micro scratches and chemicals. It is VOC compliant.

At about 20 ° C, the clear coat used has in particular a spray viscosity of 20 to 22 s 4 mm DIN. It can be applied with spray nozzles from 1.2 to 1.4 mm at pressures between 2 - 3 bar with an internal nozzle pressure of 0.7 bar. The layer thickness of the dry film is 50 to 60 µm. At an object temperature of 20 ° C to 60 ° C, the drying time is between 5 min and 24 h.

The clear coats used are acid, base and pollutant resistant.

Hardeners can be added in various proportions, e.g. Clear varnish hardener Vol. 2: 1 to 3: 1. The hardeners usually contain aliphatic polyisocyanates.

Colorless additives can be used as additives to increase the elasticity of clearcoats, e.g. Plasticizers, come. This is particularly advantageous when processing deformable plastic parts. The additives are colorless and are used in a mixing ratio of 10 - 50% additions to the base coat. The drying time using the additives may increase by up to 100%.

The coloring can be done with matt water-based lacquer or matt acrylic lacquer. The clear varnish is applied over the top for sealing. The coloring can also be done with a single-layer lacquer. This one-layer lacquer automatically seals the sprayed film. It can be matt or glossy.

The liquid rubber used is a rubber based on rubber, is elastic, resistant and easy to process. The rubber can be natural or synthetic rubber and is vulcanized. In order to make the rubber sprayable, additives such as vulcanization accelerators or retarders, fillers, organic solvents, antioxidants and / or antiozonants are usually added to improve the durability and processability.

Synthetic materials such as silicones, that is to say poly (organo) siloxanes, in particular silicone rubbers, can also be used. Silicone rubbers are masses which can be converted into the rubber-elastic state and contain poly (organo) siloxanes which have groups which are accessible to crosslinking reactions.

Further advantages of the invention are explained below:

In addition to the aesthetic aspect, the process according to the invention has a further positive benefit: the film seals and protects the underlying basecoat from scratches, the effects of weather, stone chips and other signs of wear, thereby preserving the value of the vehicle. Rims or other vehicle parts treated according to the procedure are also protected against salts in winter.

The coloring can be designed specifically according to customer requirements. For example, colors, e.g. Acrylic-based paints or solvent-based paints can be mixed with liquid rubber and single-layer paint. Special color designs are also possible, for example phosphorescent coatings that re-emit light in the dark for hours. Furthermore, fluorescent effects can be achieved, which become visible, for example, when they are exposed to UV radiation.

With the method according to the invention, complex 3-dimensional objects such as rims, radiator grilles, emblems and much more, which otherwise could not be foiled but only painted, can be processed.

Furthermore, it is advantageous that no dismantling of vehicle parts is necessary to use the method, but instead provide the vehicle with the film coating in one piece using the method according to the invention can be. This also affects the price and reduces costs. In addition, only 1-2 working days are required for coloring a complete vehicle according to the invention. In contrast to the foiling according to the prior art, this is a time saving of 50%.

It is also possible to apply transparent film. This cannot be achieved with the foils known from the prior art.

If, for example, a color change is desired, the film can easily be pulled off again and a new coloring of the vehicle or of the parts can be applied by means of the method according to the invention.

Furthermore, a vehicle or part already provided with a film according to the invention can be provided with another film according to the invention without pulling off the existing film. The "new" film can be sprayed directly onto the existing film. For example, a car sprayed in "red" today could be sprayed with "black" tomorrow.

Further advantages and advantageous embodiments of the invention can be found in the following description of the figures, the drawing and the claims.

Fig. 1

einen schematischen Ablauf des Verfahrens.

Exemplary embodiments of the solution according to the invention are explained in more detail below with reference to the attached drawing. It shows:

Fig. 1

a schematic flow of the method.

Fig. 1 represents a schematic sequence of the method. The surface to be treated is cleaned and degreased beforehand. Parts that are not to be machined may be taped off.

This is followed by the application of the liquid rubber, which is diluted for better processability. The liquid rubber can be colored with color additives. At least one layer of the liquid rubber is sprayed on, an application of four to seven layers of liquid rubber has proven to be suitable for forming a film coating. There is a drying phase after each order.

The resulting film coating is then sealed.

This can be done by applying an adhesion promoter and then applying clear coat.

When choosing specially designed clearcoats that do not require an adhesion promoter, such a clearcoat is applied and a further clearcoat is used for the final sealing.

Furthermore, a single-layer lacquer can be used to seal the liquid rubber layers.

The single-layer lacquer can achieve the desired result by adding colors or its formation (matt / clear).

Claims (4)

1. Method for coating objects, in particular vehicles and vehicle components, comprising the following steps:

   • diluting liquid rubber with an acrylic thinner

   • filling the diluted liquid rubber in a spray gun or an electric spraying device

   • applying the diluted liquid rubber on to the surface of the object to be coated by means of the spray gun or the electric spraying device

   • drying period

   • thereby formation of a removable film coating,
   wherein the application of the diluted liquid rubber occurs in four to eight layers, and in that a diluted acrylic paint is admixed to the liquid rubber having the acrylic thinner, and wherein after the application of each layer, in each case a drying period is activated,

   • mixing of clear coat with a curing agent at a ratio of 2:1

   • adding of 10 vol.-% acrylic thinner of the total amount

   • spraying of a mixture of ready-to-spray clear coat and curing agent dry on to the film coating;

   • application of 1 - 2 further wet layers, waiting for at least 10 minutes between each layer,

   • flash-off of the cleat coat after the last layer.
2. Method according to claim 1, characterized in that the air pressure upon application of the diluted liquid rubber is 2 to 4 bar.
3. Film coating for painted vehicle surfaces, comprising at least four layers of a ready-to-spray liquid rubber diluted by means of an acrylic thinner according to the film coating applied by means of the production method according to claim 1 or 2, wherein the layer of liquid rubber comprises a diluted acrylic-based paint, and at least one clear coat layer is applied on to the layers of liquid rubber, wherein the clear coat layer comprises a curing agent component.
4. Coated article, in particular vehicle or vehicle component, characterized in that it is provided with a film coating according to claim 3.

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