WO2016050829A1

WO2016050829A1 - Method of coating an article in order to imitate a natural material or a natural appearance

Info

Publication number: WO2016050829A1
Application number: PCT/EP2015/072531
Authority: WO
Inventors: Benjamin Liesch; Joseph BARBAR
Original assignee: Tmn Industries
Priority date: 2014-09-30
Filing date: 2015-09-30
Publication date: 2016-04-07
Also published as: FR3026322A1

Abstract

Method of coating an article, characterized in that it comprises the following steps: - a first layer of power paint (12) is deposited on the article (10); - next the article coated with the first layer of powder paint is baked; - after baking, a second layer of powder paint (13), then a liquid product, are applied without baking; - a third layer of powder paint (14) is deposited; and - the article thus coated with the third layer of powder paint is baked.

Description

METHOD FOR COATING AN OBJECT TO IMITATE A NATURAL MATTER OR A NATURAL APPEARANCE

The present invention relates to a method of coating an object, such as an article of decorative metalwork, to impart to it an appearance imitating a natural appearance or a natural material, such as an oxidized appearance, the wood, the Pierre, ...

International Patent Application No. WO 2005 121404 already discloses a method for producing a decorative ironwork article having an oxidized appearance by depositing, using an electrostatic spray, a first layer of a powder-based coating. pigmented polyester combining a first dark-colored powder forming a background and a second light-colored powder forming a rupture of the continuity of the colored appearance of the article. The item is then baked for cooking. The choice of light and dark colors corresponds to the desired oxidized appearance.

Another technique is described in US Pat. No. 5,728,236. The process of this patent is to produce an ornamental rust finish on a ferrous metal surface, using a liquid that rustes the metal instantaneously upon contact with the metal surface and which can be applied easily and easily. safe way by craftsmen.

European Patent Application EP 2 690 143 describes, moreover, a method for producing an oxidized surface by applying a polyester powder coating composition to a metal substrate by electrostatic spraying. This process can be monolayer or multi-layer.

Also known from US Patent Application 2006105144 is a method for making a decorative article, including applying a first polyester powder coating to a metal substrate by electrostatic spraying and performing a baking, then to implement a second coating based on polyester powder.

Means for selectively removing the second coating are also provided to give the article the desired decorative effect (wood, marble). A third layer of a powder coating is then applied.

US Pat. No. 4,317,847 discloses a method for forming, on a surface, a simulated finish of weathered wood. The surface is first coated with a dark paint and as long as it is still fresh, a second coating of lighter color paint is applied to the brush to vein it while varying the pressure of the brushing in order to vary the amount of mixing with the first coating. A third, still lighter, coating is then applied to the second coating on the second coating as long as the latter is still moist to vein the second coating while varying the brushing pressure in a similar manner to vary the thickness of the coating. importance of mixing with the second coating. The disadvantage of these methods is that none of them can faithfully reproduce color variations existing in the natural state.

The present invention aims to provide a coating process overcoming this disadvantage and leading, in addition, to other advantages.

It proposes, for this purpose, a method of coating an object, comprising the following steps:

a first layer of powder paint is deposited on the object;

the object coated with the first layer of powder paint is then fired;

- After baking, a second layer of powder paint is applied, followed by a liquid product without cooking;

- a third layer of powder paint is deposited; and

the object thus coated with the third layer of powder paint is baked. The implementation of this succession of steps allows to obtain coated objects whose appearance is truer than nature.

The choice of the colors of the different powder paints makes it possible to obtain the type of oxidized appearance desired, such as, for example, oxidized iron, oxidized copper, oxidized lead or oxidized bronze, or imitation of material. sought such as including wood and stone.

The object may, for example, be of any material resistant to cooking for fixing the layers of paint and more particularly, a metal object (metal or alloy), a glass object, wood or an object of a material composite.

One or more of the powder coatings may be based on pigmented polyester powders, in particular because of their good resistance to UV and weather in the context of outdoor use.

Powder coatings are, according to one embodiment, deposited by electrostatic spraying, but other methods can also be implemented, such as a fluidized bed process including fluidized bed soaking.

According to one embodiment, the cooking is carried out in the oven at a temperature depending on the nature of the object. As an indication for a metal object, of the order of 180 ° C for aluminum and 200 ° C for steel. Other metals such as cast iron can of course be used.

According to yet another embodiment, the liquid product is a mixture of organic compounds with high flash point. It is a particular embodiment of a mixture comprising 5% butoxy-ethanol, 5% sodium pyrophosphate, 5% sodium metasilicate and 5% alcohol ethoxylates in a water solution demineralized. It can be applied by spray, brush, brush or pad.

Alternatively, the liquid product is an organic solvent, preferably hydrocarbon or oxygenated. It may be, for example, white spirit, turpentine, solvent naphtha VMP (solvent used for the manufacture of varnish and paint, the abbreviation "VMP" corresponding to the English expression "varnish makers' and painters'") or an industrial alcohol.

The industrial alcohol is preferably based on methanol and / or ethanol.

These solvents can be used at different concentrations of constituents depending on the effect and / or depth of relief that is desired.

An anti-corrosion treatment (galvanization, primer, metallization, cathaphoresis) can also be applied to a metal object before the implementation of the coating process described above. In addition, any final layer of varnish may be applied after baking the third layer of powder paint.

In practice, the object may be constituted by an article of decorative metalwork such as a visor and, more generally, various structures (sheet metal, for example steel, profiled, railing, ....).

Non-limiting exemplary embodiments will now be described in support of the single figure, schematically illustrating an object to which the coating method according to the present invention has been applied.

The object shown in this figure is, for example, an aluminum railing 10 coated with a layer 1 1 of protection against corrosion which is, in practice, here, obtained by anodization.

A first layer of paint based on pigmented polyester powder 12 is then deposited on the anticorrosive protection layer 11 by electrostatic spraying.

Baking of the object thus coated with the first layer of powder paint 12 is then carried out in the oven, at a temperature of the order of

180 ° C.

After this firing, a second layer of powder paint 13 based on pigmented polyester powder is deposited by electrostatic spraying, before the application of a liquid product formed of a mixture of organic compounds with high flash point (for example that defined more precisely supra). The latter is applied, here, with the pistol.

Once this liquid product has been applied, a third layer of powder paint 14 based on pigmented polyester powder is deposited by electrostatic spraying and, finally, baking at a temperature of the order of 180.degree. once the object thus coated with the third layer of powder paint.

As has been shown very schematically in this figure, the surface coating 14 thus has a very particular relief, in practice a succession of corrugations, resulting from the implementation of this succession of very specific steps of application, including the effect is a perfect reproduction of a variation of hues existing in the natural state in the case of oxidation.

In practice, to obtain for example an oxidized appearance, as can be the case here for example with the aluminum railing 10, is associated as pigmented polyester powders brown and green color powders.

On the other hand, to obtain a wood effect, the tones will go more from brown to ocher whereas to obtain a marbled effect, one will opt more for tones ranging from white to pink.

To obtain the veined effect of wood, it will also prefer a brush application of the liquid product.

Although the invention has been described with reference to the particular embodiment thereof, it will be readily understood by those skilled in the art that changes in form and detail can be made without departing from the scope of the present invention. 'invention.

Claims

1. A method of coating an object, characterized in that it comprises the following steps:

- depositing a first layer of powder paint (12) on the object (10);

the object coated with the first layer of powder paint is then fired;

- After baking, a second layer of paint (13) powder is applied, then a liquid product without cooking;

- a third layer of powder paint (14) is deposited; and

the object thus coated with the third layer of powder paint is baked.

2. Method according to claim 1, characterized in that at least one of the first, second and third layers of powder paint is made from a pigmented polyester powder paint.

3. Method according to claim 1 or 2, characterized in that at least one of the first, second and third layers of powder paint is deposited by electrostatic spraying or by a fluidized bed process.

4. Method according to any one of claims 1 to 3, characterized in that the cooking is performed by passing the object in a furnace.

5. Method according to any one of claims 1 to 4, characterized in that the liquid product is a mixture of organic compounds with a high flash point, preferably a mixture comprising 5% butoxy-ethanol, 5% pyrophosphate sodium 5% sodium metasilicate and 5% alcohol ethoxylates in a demineralised water solution.

6. Method according to any one of claims 1 to 4, characterized in that the liquid product is an organic solvent, preferably hydrocarbon or oxygenated.

7. Process according to claim 6, characterized in that the organic solvent is white spirit, turpentine oil, VMP naphtha solvent or an industrial alcohol.

8. Method according to any one of claims 1 to 7, characterized in that the liquid product is applied by spray, brush, brush or by means of a buffer.

9. Method according to any one of claims 1 to 8, characterized in that the object is a metal object, a glass or wooden object or an object made of a composite material.

10. Method according to any one of claims 1 to 9, characterized in that an anti-corrosion treatment is applied to a metal object before the deposition of the paint layers.

1 1. Process according to any one of claims 1 to 10, characterized in that a final layer of varnish is applied after baking the third layer of powder paint.

12. Method according to any one of claims 1 to 1 1, characterized in that the object is constituted by an article of decorative metalwork, a sheet, a guardrail or a profile.