WO2010108960A1

WO2010108960A1 - Coated formwork element

Info

Publication number: WO2010108960A1
Application number: PCT/EP2010/053842
Authority: WO
Inventors: Dieter Ostermann
Original assignee: Odb-Tec Gmbh & Co.Kg
Priority date: 2009-03-25
Filing date: 2010-03-24
Publication date: 2010-09-30

Abstract

The invention relates to a formwork element (1) for concrete, in particular a formliner, having at least one formwork surface (1a). According to the invention, the formwork element (1) is characterized in that the at least one formwork surface (1a) is coated with a film (2), the film (2) being provided with a cover layer (3) at least on the side facing away from the formwork surface (1a), the cover layer (3) being designed as a lacquer layer (3) containing nanoparticles. The invention further relates to a method for producing such a formwork element (1).

Description

Coated formwork element

The invention relates to a formwork element for concrete, in particular formwork panel, with at least one formwork surface.

Shuttering elements of various geometries, in particular plate-shaped shuttering elements are known from concrete and reinforced concrete construction in a variety of designs for decades. Increasingly, there is also the need for switched concrete parts to make their surface aesthetically pleasing, in order to use them as a design element, for example, in a building facade can. To meet these aesthetic requirements, the removal of the formwork elements after the setting of the fresh concrete must be done in such a way that the risk of chipping off parts of the concrete facade due to local adhesion to the formwork element or a clamping with the formwork element is excluded. Furthermore, the frequently used formwork element may not be damaged when removing.

From practice, it is therefore known to provide the formwork surfaces of the formwork elements before use with a - usually oily - release agent, so that a problem-free detachment of the formwork elements is ensured. However, the application of the release agent requires a cost reasons generally unacceptable additional Time, since the formwork elements must be transported after a few uses for the purpose of cleaning and reapplication of the release agent from the site to a specialized company and back again.

Furthermore occur in release-coated formwork elements by inaccurate order of the release agent again and again errors that require time-consuming rework. Especially for larger construction projects, the logistics on site is burdened by the cleaning and preparation process for the formwork element. In addition, in various applications, for example in the production of drinking water storage tanks made of concrete, the use of formwork oil as a release agent for reasons of hygiene excluded.

Formwork panels are known in practice, which are coated on their formwork surfaces with a melamine resin layer as a permanent release layer. Here, the problem arises that the melamine resin layer tends to crack, so that the layer is partially infiltrated by the fresh concrete after a few uses of the shuttering element so coated, so that it is destroyed in a relatively short time.

From the patent literature a large number of formwork elements with different coatings are known:

In DE 93 00 109 Ul is a multi-layered

Shuttering plate described which as the outermost shuttering a layer of a mixture of Polyolefin resins and wood or cellulose materials, in particular wood flour has. This is described as abrasion resistant and is characterized by a low absorption capacity of water and oils, so that an easy detachment is guaranteed by the hardened concrete. In practice, however, has shown that the Äblöseverhalten no longer meets today's standards.

In AT 255 736 a formwork panel is described in which the formwork surface with a two-layer

Resin layer is occupied. In detail, the pores of the shuttering surface are filled by a first synthetic resin layer. On the surface of this first layer, a paper layer is placed, which in turn is then covered by a further synthetic resin layer, so that an overall smooth, water-repellent surface is obtained. However, such coatings of the formwork surfaces have not proven to be sufficiently resistant in practice.

Another plastic-coated formwork panel is described in DE 199 32 335 Al. It is described as being particularly resistant to aging and weathering as well as resistant to the effects of chemicals and mechanical stress. However, it does not provide a solution to the problem of difficulty in removing the shuttering element from the hardened concrete.

Finally, DE 102 56 361 B4 discloses a shuttering panel for producing concrete and reinforced concrete structures, in which a plate-shaped wood core is covered on both sides with layers of wood flour-filled polypropylene (HMPP), the HMPP layers in turn being coated with polypropylene are coated. The entire layer structure is used in a frame construction, which gives the formwork panel increased rigidity. Again, there is the problem of a non-optimal removability of hardened concrete.

Based on the above-discussed prior art, the present invention seeks to provide a formwork element for concrete, which is characterized by improved removability and surface quality of the molded concrete surface even after a large number of uses of the formwork element.

The object is achieved by a formwork element for concrete, in particular a formwork panel, with at least one formwork surface in that the at least one formwork surface is coated with a film, wherein the film is provided at least on the side facing away from the formwork surface with a cover layer, wherein the Cover layer is formed as a lacquer layer containing nanoparticles.

The inventively provided at least on the side facing away from the formwork surface of the film, containing nanoparticles lacquer layer acts as a permanent separation layer for the formwork surface of the formwork element.

Due to the minimal inner surface of the lacquer layer, a mechanical clawing of the concrete in the layer is effectively prevented, so that optimum removability of the concrete surface is ensured. Concrete surfaces that were created with shuttering elements according to the invention remain oil-free and thus adhesive for applied mineral plaster and paints.

Furthermore, as a result of the nanoparticles finely distributed in the paint binder as elastic matrix, the coating has excellent abrasion resistance (abrasion resistance and scratch resistance), so that the moldings coated according to the invention can still be used without problems even under the most unfavorable conditions with respect to mechanical stress. Accordingly, the risk of damaging the coating can be minimized even with a robust treatment of the coated panels on construction sites.

Furthermore, the use of the lacquer layer with the nanoparticles contained therein makes it possible to achieve a high level of smoothness of the shuttering surface, since pores present in the shuttering surface are closed by the combination of foil and lacquer layer applied thereon. Accordingly, the concrete surface molded thereon can potentially meet the highest aesthetic demands. In investigations of the Applicant, average roughnesses of R _{3 '} <1 nm could be achieved.

Because the lacquer layer containing the nanoparticles is not applied directly to the formwork surface of the formwork element but onto the film, the film itself being attached, preferably glued, to the formwork surface, the coating process can be carried out much simpler and less expensively than in the case of one also possible - direct coating of the formwork surface with the nanoparticle-containing paint. For example, the coating of the film in a roll-to-roll process is possible. Overall, existing production capacities for coating films can be used by coating companies, which reduces investment costs. Films also facilitate the recycling of damaged formwork panels.

The formwork element in turn can have a wide variety of geometries. Conceivable are plate-shaped as well as spherical or angled geometries. Furthermore, the

Shuttering be made of different materials. Suitable examples are polymeric materials or metallic materials. Wood-based materials are particularly widespread in the field of concrete formwork, as they are available at low cost and are mechanically robust.

It is understood that the formwork element according to the invention in addition to concrete for other formable materials is suitable, especially for those with hydraulic binders such as gypsum, lime, clay and more.

A particularly efficient use of the lacquer layer containing nanoparticles is ensured if the foil is coated on one side with the lacquer layer containing the nanoparticles on the side remote from the formwork surface of the formwork element.

As paints commercially available coating systems can be used. Acrylic resin coatings, in particular based on

Pentaerythritol triacrylate or pentaerythritol tetracrylate. Particularly suitable are radiation-curable lacquers, such as, for example, curable acrylic resin paints. Also usable are other synthetic coating systems, such as alkyd resins, which are characterized by a special hydrophobicity. Also, the use of natural resins is conceivable. By appropriate selection of the paint system is a very high resistance of the shuttering surface against chemicals, such as various solvents, alkalis, acids various foods and oils, achieved in a wide pH range and long-term UV stability.

According to the paint system contains nanoparticles. The nanoparticles can be formed by a variety of substances (metals, semi-metals or metal oxides). Particularly suitable materials are those which also have a corresponding microscopic hardness in order to impart the desired macroscopic abrasion resistance to the lacquer layer applied to the shuttering surface and containing the nanoparticles. Nanoparticles are particularly suitable for use with semimetal oxides, in particular silicon dioxide (SiO ₂ ).

In order to achieve the desired properties, the proportion of nanoparticles in the applied and cured lacquer layer is preferably about 60 to 75% by weight, particularly preferably about 75% by weight.

The nanoparticles may have an average diameter of about 1 to about 200 nm, in particular 10 to 15 nm, preferably 10 nm.

The paint to be applied to the formwork surface can be produced by a sol-gel process, as is known per se from the prior art. He is different Solvent dilutable so that the desired processing properties can be precisely adjusted. If, for example, ethanol is used as the solvent, the processable lacquer at an ethanol content of about 70% by weight has a solids content (lacquer binder with nanoparticles) corresponding to about 30% by weight, a density of about 0.876 g / cm ³ and a viscosity of 2.3 mPa · s.

The proportion of solvent in the workable lacquer layer may be about 70% by weight to about 90% by weight.

The brought into a processable state paint can be applied in different ways preferably directly on the film of the formwork element. Suitable application methods are, for example, spraying, knife coating, printing or rolling.

In this case, preferably a dry film thickness d <10 microns, for example 7 - 8 microns, adjusted, which is easily possible with the above techniques. Investigations by the Applicant have shown that at higher layer thicknesses under mechanical stress, there is a build-up. Furthermore, investigations by the applicant have shown that a paint consumption of 15 g / m ² results at a set dry film thickness of 5 μm.

The film used in the formwork element according to the invention is preferably made of a polymeric material. This polymeric material is preferably a material from the group polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), acrylonitrile-butadiene-styrene copolymer (ABS), acrylic ester-styrene-acrylonitrile (ASA), polyvinyl chloride (PVC), polyetheretherketone (PEEK), polyethylene (PE) and polypropylene (PP). In the case of polyethylene (PE) and polypropylene (PP), it has proven to be advantageous to perform a surface treatment before the coating in order to ensure a primerless coating, eg fluoridation, corona discharge.

The thickness of the film can assume different values. Particularly preferred is a thickness <1 mm. As a result, sufficient flexibility of the film is ensured at the same time sufficient mechanical resistance.

According to a particularly advantageous embodiment of the invention, the film is formed as a self-adhesive film, wherein the one film surface is provided with the paint layer and the other surface is provided with an adhesive layer, wherein the film is adhered to the formwork surface of the formwork element. By using a one-sided self-adhesive film, a particularly simple attachment of the film to the formwork surface of the formwork element can be achieved without the use of an additional adhesive would be required. Further, the conventional method of applying films to chipboard (compression under temperature and pressure) can be applied.

The invention is further based on the object, a method for producing a formwork element for concrete, in particular a formwork panel, with at least one

Specify formwork surface, which is characterized by a simple feasibility and low cost and which ensures the production of release agent-free formwork elements with high surface quality and service life.

The object is achieved by a method according to the preamble of patent claim 15, the method comprising the following method steps:

- At least one-sided coating of the film with the nanoparticle-containing paint layer and

- Applying the coated film on the formwork surface of the formwork element, wherein the lacquer layer containing nanoparticles is arranged on the side facing away from the formwork surface of the film.

The method can be implemented with low system complexity and can be carried out with high process reliability. This has a labor-saving effect that the film for the coating process does not need to be specially pretreated. It is understood that for the coating with the nanoparticles containing paint layer, as in a

Paint coating usual, a substantially clean and fat-free surface must be present.

For the formwork elements produced by the method according to the invention, the advantages mentioned above apply correspondingly.

Specifically, it is possible to coat the film with high throughput in a coating unit, for example in the roll-to-roll process, wherein the lacquer layer is sprayed onto the film surface by means of a slot die. Alternative to spraying The coating can also be applied by doctoring, printing or rolling. Again, the fast roll-to-roll process is suitable.

The coating layer applied in such a way or in another way to the film can then be radiation-hardened, in particular by UV radiation.

According to a particularly advantageous embodiment of the method, the film on the shuttering surface of the

Shuttering element are glued, wherein the film is formed as a self-adhesive film and wherein the one film surface is provided with the paint layer and the other surface is provided with an adhesive layer.

This allows a particularly fast and secure attachment of the film on the formwork surface of the formwork element.

In practice, the method can be carried out, for example, as follows:

First, the film is coated in a coating unit, preferably in a roll-to-roll process, with the lacquer layer containing nanoparticles. Subsequently, the thus coated film is transported to save space in bales to the manufacturer of the formwork elements, where it is applied to the formwork surface of the formwork elements, in particular glued, is. Subsequently, the ready-to-use formwork elements are transported to the construction site, where they are intended for appropriate concrete work. Alternatively, it is possible first to attach the film to the formwork surface of a formwork element - for example, the manufacturer of the formwork elements - and then with the nanoparticles containing

Coat lacquer layer. However, this does not take advantage of the time advantage associated with large-scale film coating in a coating plant.

It is understood that the attachment of the film to the

Formwork surface as well as the coating of the film can also be done on site on a construction site.

As a result, it becomes clear that the order of the method steps to be carried out is not fixed in principle.

A further aspect of the invention relates to the use of a body partially coated with a nanoparticle paint layer, in particular a one-sided coated plate-shaped body, as a formwork element for concrete.

Another aspect of the invention relates to the use of a coating at least partially coated body, in particular a one-sided coated plate-shaped body, as a formwork element for concrete, wherein the coating comprises a film, wherein like film on the side facing away from the body with a lacquer layer containing nanoparticles is coated. The aforementioned advantages again apply accordingly.

In the following the invention will be explained in more detail with reference to a drawing illustrating an embodiment. The single FIGURE shows a formwork element 1 in a side partial sectional view, for the sake of clarity no true to scale representation was selected.

The shuttering panel 1 is in this case made of a wood material and formed plate-shaped. Likewise, the formwork panel may be made of a plastic or metal.

The formwork panel 1 comprises a formwork surface Ia, which in the present case is stuck with a self-adhesive film 2. The adhesive layer is designated 2a. The film 2 consists of a polymeric plastic, such as polycarbonate, and has a thickness of <1 mm, in this case 0.5 mm. On the side of the film 2 applied to the formwork surface 1a of the formwork panel 1, the film 2 is coated with a lacquer layer 3 containing a nanoparticle with a dry film thickness of <10 .mu.m. The binder of the lacquer layer 3 is presently an acrylic resin, in particular based on pentaerythritol triacrylate or pentaerythritol tetracrylate. The

Nanoparticles are presently formed by silicon dioxide particles with an average diameter of about 10 nm. The proportion of nanoparticles in the paint layer 3 is about 75% by weight.

With the coated formwork panel 1 shown, the impression of an aesthetically high-quality concrete surface allows. Furthermore, the standing in contact with the fresh concrete paint layer 3 has an excellent abrasion resistance, so that the coated with the film 2 formwork panel 1 even after many applications even under the most adverse conditions with respect to a mechanical stress is still easy to use.

Claims

claims

1. formwork element (1) for concrete, in particular formwork panel, with at least one formwork surface da), characterized in that the at least one formwork surface (Ia) with a film (2) is coated, wherein the film (2) at least on the formwork surface ( Ia) facing away from the side is provided with a cover layer (3), wherein the cover layer is formed as a lacquer layer (3) containing nanoparticles.

2. Shuttering element (1) according to claim 1, d a d u c h e c e n e c e s e s, the film (2) on one side of the formwork surface

(Ia) of the formwork element (1) facing away from the nanoparticles containing lacquer layer (3) is coated.

3. Shuttering element (1) according to claim 1 or 2, characterized in that the binder of the lacquer layer (3) containing the nanoparticles is an acrylic resin, in particular based on pentaerythritol triacrylate or pentaerythritol tetracrylate.

4. Shuttering element (1) according to one of claims 1 to 3, d a d e r c h e c e n e c i n e s t, that is, the lacquer binder UV-cured.

5. Shuttering element (1) according to one of claims 1 to 4, characterized in that the nanoparticles of the lacquer layer (2) are at least partially formed by half metal oxide particles, in particular SiO ₂ particles.

6. Shuttering element (1) according to one of claims 1 to 5, in which the nanoparticles are essentially spherical and have an average diameter of 1 to 200 nm, in particular 10 to 15 nm, particularly preferably 10 nm.

7. Shuttering element (1) according to any one of claims 1 to 6, d a d e r c h e c e n e c e n e, t a s s the proportion of nanoparticles in the cured lacquer layer is 60 to 75% by weight, preferably 75% by weight.

8. Shuttering element (1) according to one of claims 1 to 7, characterized in that the lacquer layer (3) is applied directly to the film surface.

9. The formwork element according to claim 1, wherein the lacquer layer is applied to the film surface by spraying, knife coating, printing or rolling.

10. Shuttering element (1) according to claim 1, wherein the lacquer layer (3) has a dry thickness d of less than 10 [mu] m.

11. Shuttering element (1) according to any one of claims 1 to 10, d a d e r c h e c e n e c i n e s, e e s the film (2) is made of a polymeric material.

12. Shuttering element (1) according to claim 11, characterized in that the polymeric material is a material of the group polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), acrylonitrile butadiene

Styrene copolymer (ABS), acrylic ester-styrene-acrylonitrile (ASA), polyvinyl chloride (PVC), polyetheretherketone (PEEK), polyethylene (PE) and polypropylene (PP).

13. Shuttering element (1) according to one of claims 1 to 12, characterized in that the film (2) has a thickness of <1 mm.

14. Shuttering element (1) according to one of claims 1 to 13, characterized in that the film (2) is designed as a self-adhesive film, wherein one film surface is provided with the lacquer layer (3) and the other surface with an adhesive layer (2a) is provided, wherein the film (2) is glued to the formwork surface (Ia) of the formwork element (1).

15. A method for producing a formwork element (1) for concrete, in particular a formwork panel, with at least one formwork surface (Ia), according to one of claims 1 to 14, e e c e n e c e by the following method steps:

- At least one-sided coating of the film (2) with the nanoparticle-containing paint layer (3) and

- Applying the coated film (2) on the formwork surface (Ia) of the formwork element (1), wherein the nanoparticles-containing lacquer layer (3) on the shuttering surface (Ia) facing away from the film (2) is arranged.

16. The method according to claim 15, characterized in that the lacquer layer (3) is applied directly to the film surface.

17. A process according to claim 15 or 16, wherein the film (2) is coated in a roll-to-roll process.

18. The method of claim 15, wherein the film is coated by spraying, knife coating, printing or rolling.

19. A method according to any one of claims 15 to 18, wherein said paint resist is cured by UV radiation.

20. The method according to any one of claims 15 to 19, characterized in that the film (2) is glued to the shuttering surface (Ia) of the shuttering element (1), wherein the film (2) is designed as a self-adhesive film (2) and the one Film surface is provided with the paint layer (3) and wherein the other surface with an adhesive layer (2a) is provided.

21. Use of a nanoparticle-containing

Lacquer layer at least partially coated body, in particular a one-sided coated plate-shaped body, as a formwork element for concrete.

22. Use of a coating at least partially coated body, in particular a one-sided coated plate-shaped body, as a formwork element for concrete, wherein the coating comprises a film, which is coated as film on the side facing away from the body with a resist layer containing nanoparticles.