DE102014209787A1 - One-component water-based decal - Google Patents

Abstract

The present invention relates to a one-component strippable with water as the solvent in a proportion of at least 50 wt .-%, that is substantially water-based, wherein the strippable further contains at least one co-solvent, which has a higher boiling point than water; wherein the Abziehlack contains a total of organic solvents only in a small proportion, that is highly environmentally friendly.

Description

The present invention relates to a one-component stripping lacquer with water as solvent in an amount of at least 50 wt .-%, ie a strippable, the substantially water-based voliegt, wherein the Abziehlack further contains at least one co-solvent, which has a higher boiling point has as water, that is less strongly evaporated / evaporated than water, the Abziehlack contains a total of organic solvents only in a small proportion, that is highly environmentally friendly.

Abziehlacke are known in principle from the prior art, in particular as a replacement for applied as separate components films. A well-known application paint for peel-off is the covering of areas of a surface, which is then to be permanently painted. The Abdecklack protects the non-painted areas of the surface.

Such prior art topcoats are before use in two or more components before and / or contain a significant proportion of organic solvents which have a high vapor pressure and in many applications for reasons of environmental protection are not useful. A two-component peel-off is for example from the WO 97/35932 known.

Thus, it is an object of the present invention to provide an environmentally friendly strippable finish. This object is achieved by the protection mentioned in claim 1 Abziehlack. Preferred embodiments will be apparent from the dependent claims.

The present invention relates to a strippable lacquer which is present on a surface in a single component ("one-component system") prior to its application and which is essentially based on water as solvent, ie organic solvents of less than 10 wt. %, preferably less than 5% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight (in each case% by weight, based on the total weight of the stripping lacquer). Thus, in the present case, the formation and curing of a permanently elastomeric polymer film primarily begins with the volatilization of water.

In the context of the present invention, the strippable lacquer comprises a dispersion, ie a two-phase system comprising at least one solid component, in the present case at least one polymer component, which is present in incompletely soluble form in a liquid component, preferably in the form of polymer beads liquid component contains water, preferably, as defined above consists essentially of water.

The polymer component contains at least one polyurethane and / or at least one acrylate, preferably an aqueous polyurethane-polyurea dispersion is present. Furthermore, the dispersion preferably contains at least one adhesion-promoting additive which adheres to smooth substrates and is further preferably designed such that it contains a hydrophilic functionality as well as a hydrophobic functionality.

The strippable lacquer in the sense of the present invention is used in particular for the (over) lacquering of smooth surfaces, in particular without having to grind them before, with the aim of protection and / or design of smooth non-absorbent (not water-absorbing) surface structures. In this case, the Abziehlack evaporable organic components ("VOCs") only to a small extent and is therefore particularly suitable for commercial and residential applications, especially in the context of prescribed by law VOC regulations, for example, for vehicle painting and the private use of painting furniture , Recreational and construction and industrial applications.

A "peel-off" in the context of the present invention is a mechanically and chemically durable (durable) and permanently elastomeric polymer film which is applied to a smooth, non-water-absorbing surface and from this, even after a long period of time, by purely mechanical means and without chemical change of the surface and / or without thermal treatment can be deducted again.

Thus, the strippable lacquer according to the present invention does not necessarily serve merely a "temporary" protection of a surface, but, unlike the prior art, also for a prolonged coating which does not fulfill (only) protective functions, but also, for example, decorative functions.

A polymer film applied and cured on a surface, which is based on a strippable lacquer according to the invention, can be removed from the surface without residues for up to one year, preferably up to two or five years, preferably after an even longer period of time.

Peel-off in the context of the present invention are preferably applied to already (permanently) painted surfaces, so serve not only the protection of surfaces, but also their independent color design.

A significant advantage of the present invention is that with the help of the Abziehlackes invention a large color selection can be made and different levels of gloss can be adjusted, from high gloss to various dullness levels. Furthermore, the fact that water is used as an essential solvent, environmental and technical advantages, in particular, the work is possible without special precautions and working in confined spaces (low concentration of VOC). Due to the low content of volatile organic components, the relevant legal provisions of the VOC regulation are also complied with.

Due to its non-aggressive nature, the stripping lacquer according to the invention does not dissolve substrates and does not discolour on different substrates, in contrast to known solvent-based products.

For the purposes of the present invention, the strippable lacquer preferably contains thickeners, stabilizers and / or emulsifiers in the aqueous phase, which correspondingly slow down the settling of the particles and bring about a sufficient storage stability.

Such stabilization is preferably achieved by a polyethylene oxide component in the polymer; or by anionic components containing carboxyl or sulfonate, or by cationic components such as, for example, amine groups. Accordingly, for the purposes of the present invention, the stripping lacquer may be nonionic, anionic or cationic.

In a preferred embodiment, the polymers in the stripping lacquer are present as particles which are preferably substantially spherical and which are more preferably in the size range from about 30 nm to 100 μm, in particular in the range from 30 nm to 1000 nm, particularly preferably. The particle size distribution can be monomodal, bimodal or multi-modal.

The drying of the release lacquer applied to a surface (which then becomes a release liner) can take place at room temperature, but also at elevated temperatures, depending on the design of the substrate which forms the surface. Curing at room temperature is preferred.

The mechanism of the curing process of the release lacquer applied to a surface is shown in FIG 1 illustrated. This mechanism is to be understood only as an explanatory proposal and not as binding. In this case, the adhesion-promoting additive with a hydrophilic and hydrophobic group on the smooth substrate initially forms "adhesion points" for the applied dispersion, which adheres particularly well to the surface due to this adhesion-promoting additive. A component essential for the film formation is the cosolvent, which has a higher boiling point than water, that is, evaporates or evaporates more slowly than water. The co-solvent enables film formation of the peel-off at room temperature by "dissolving" the surfaces, even after the evaporation of the water already begins. There is thus a "coalescence" instead. The co-solvent continues to evaporate without further heat treatment and the film becomes progressively harder. Typically, the release lacquer applied on a surface, then as a film, will reach its final strength in five to seven days. 2 shows a cross-sectional view of a on a surface (here: fabric) peelable paint according to the invention.

The co-solvent of the invention is compatible with water, so it can be diluted with water. As already mentioned above, the co-solvent also has a higher boiling point than water, that evaporates / evaporates less quickly than water.

The proportion of co-solvent is preferably 50 g to 100 g per liter of stripping paint.

In one embodiment, the release lacquer, prior to use, has a density in the range of 1.05 g / ml to 1.25 g / ml, preferably 1.15 ± 0.05 g / ml.

In addition to the components already mentioned above, the stripping lacquer also contains other additives, in particular pigments (dyes) which serve to color, and thickeners, emulsifiers and / or stabilizers, which stabilize the dispersion for storage and transport and counteract sedimentation.

The Abziehlack invention has a comparatively high solids content, in particular 20% -60%, preferably 40% -55% (in each case% by weight based on the total weight of the Abziehlackes) and thus has advantages in terms of transport and storage and the achievable dry film thicknesses. After applying the Abziehlackes on a surface is achieved by the high solids content more effective drying per mass fraction, since less energy must be expended to evaporate the solvent.

The stripping lacquer according to the invention can be applied to a surface with all application methods known to the person skilled in the art, in particular lacquered with spray devices, rolled or knife-coated or applied with a brush become. An immersion coating is also possible in the sense of the present invention.

For the purposes of the inventive method for applying the Abziehlackes the Abziehlack should be applied area-wide and homogeneous on the surface, with a thickness of at least 150 nm, to ensure that the then dried and cured film can be removed without residue. It is particularly preferred that the thickness of the release lacquer applied to a surface after application has a thickness of 10 .mu.m to 100 .mu.m, preferably from 10 .mu.m to 50 .mu.m, more preferably from 15 .mu.m-25 .mu.m. For highly elastic coatings, a layer thickness of 40 μm to 80 μm is advantageous.

It is particularly preferred that the Abziehhlack with "airless", "Airmix", electrosprayers, suction devices or gravity cup guns is applied.

The resulting release liner, which is applied and cured on a surface, can be removed without residue from the surface by simple mechanical removal, ie without the aid of chemical and / or thermal measures, in particular without the underlying surface, even if this before application of the Abziehlackes already permanently painted was to damage. The fact that the cured Abziehlack can be removed as a film from the surface without residue is, according to this view, without being bound to this proposed mechanism to be bound by the presence of a co-solvent and optionally - in interaction with it - the adhesion-enhancing additive conditionally.

For the purposes of the present invention, an "adhesion-promoting additive" relates to a component of the stripping lacquer which can interact both with the surface to be coated and thus adhere to it, and also interacts with the polymers in the strippable lacquer. In this case, the adhesion-promoting additive preferably has a hydrophilic functional group and a hydrophobic functional group.

According to the in 1 As shown, the adhesion-promoting additive attaches directly to the surface to be coated and, in cooperation with the cosolvent, which evaporates or evaporates more slowly than water, ensures that the film applied to the surface remains homogeneous on the one hand and can cure on the other hand that a homogeneous coating is guaranteed.

In contrast to peel-off films known from the prior art, the (slowly) cured peel-off film has a hardness comparable to that of a permanently applied and cured lacquer based on a release lacquer applied to a surface in the sense of the present invention. For example, the hardness may be given as "Martens hardness" (MH), as with an instrumented indentation test DIN EN ISO 14577 with a microhardness measuring device, for example "Fischer Scope HM 2000". In this case, hardnesses MH of 10 to 100 N / mm ^{2 are} preferred, in particular hardnesses of 30 to 80 N / mm ² .

The preferred range of application in terms of temperature, for the present stripping paint, is from + 5 ° C to + 55 ° C.

In a preferred embodiment, the cured Abziehlack, now present as a film, an extensibility of 350% to 800%.

Preferred applications and embodiment

The strippable lacquer according to the present invention is preferably used as a topcoat lacquer for the protection of a first permanently applied lacquer, in particular protection against acid rain, UV radiation, mechanical damage. In this context, or independently thereof, the Abziehlack invention also allows in particular the Farbtongestaltung by a liquid film on IObjekten, such as vehicles of any kind, as well as in the field of design options. Glass design, furniture design Facade design Advertising technology and art objects. The stripping lacquer according to the invention is also suitable for protective sealings with regard to dirt and as a water-repellent film as well as an anti-graffiti protective layer which can be completely removed again.

The stripping lacquer according to the invention is also suitable as a precoat for protective sealing, for applying a colored or uncolored protective layer against dirt, a water-repellent layer, or a layer which serves to protect against the application of graffiti or particularly facilitates the removal of graffiti from the surface. In this sense, the Abziehlack invention also serves as a sealing varnish, which can be removed from the object to be protected without residue and completely.

The stripping lacquer according to the invention can be applied (applied) directly, in particular without pre-cleaning of the surface, which was preferably not subjected to any sealing, in particular no wax seal, without prior grinding work conventional spray guns having a nozzle size in a range of 1.2 to 1.4 mm. An injection pressure of about 2 bar in the "wide jet mode" has proven to be particularly advantageous.

The strippable lacquer according to the present invention is preferably used for applications (applications) on surfaces, in particular large-area surfaces. After use, the water evaporates or evaporates as well as the co-solvent present in the dispersion of the stripping lacquer and thus leads to curing and to an elastic film containing, in particular, the polymer component, optionally with pigments, as a coherent (coherent) film.

The clearcoat of the invention can be diluted with about 5 to 10% of a diluent. In the exemplary embodiment care was taken not to pre-paint thin and dry. It has been found to be recommended that the surface to be coated is preferably painted with two to four spray passes. It is important to ensure that the tail and edges are coated as evenly as possible. In this exemplary embodiment, the drying is advantageously carried out at 60 ° C convection temperature over a period of 20 to 30 minutes. Drying in air lasts up to 24 hours in the drying area and the final hardness, in both types of drying, is reached after about one week. The resulting release liner, which is applied and cured on a surface, can be removed without residue from the surface by simple mechanical removal, ie without the aid of chemical and / or thermal measures, in particular without the underlying surface, even if they are already permanently painted was to damage.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 97/35932 [0003]

Cited non-patent literature

• DIN EN ISO 14577 [0031]

Claims (8)

Stripping lacquer containing water as solvent in an amount of at least 50% by weight, preferably at least 70% by weight, more preferably at least 90% by weight, in each case based on the total weight of solvent, further comprising at least one co-solvent which has a higher boiling point than water; the stripping lacquer containing organic solvents in a proportion of at most 10% by weight, preferably at most 5% by weight, more preferably at most 2% by weight, based in each case on the total weight of the stripping lacquer, wherein the stripping paint, prior to its application on a surface, is present as a single component ("one-component system"), which single component is a dispersion of at least one polymer, preferably in spherical form, in said solvent. Stripping paint according to claim 1, characterized in that the dispersion also has at least one adhesion-promoting additive, which preferably can interact both with the surface to be coated and with the polymers. Stripping paint according to claim 1, characterized in that the dispersion further contains additives such as emulsifiers, thickeners, stabilizers and / or pigments, as well as combinations thereof. Stripping paint according to one of the preceding claims, characterized in that the polymer is selected from the group comprising polyurethanes, polyureas, acrylates and methacrylates, in particular polyurethane-polyurea mixtures. Stripping varnish according to one of the preceding claims, characterized in that the varnish is available in various colors and colors, such as uni, metallic, effect, glitter, (white, black, red, green, blue, yellow), transparent colorations, glitter coloring or self-coloring, as well as neon, thermoactive pigments, afterglow or neon pigmentation, or their inks. Method for applying the Abziehlackes according to any one of the preceding claims, characterized in that the Abziehlack with airless, Airmix, electrosprayers, suction and gravity cup guns, or with dipping method, brush or squeegee or foam rollers is applied. Use of the Abziehlackes according to any one of the preceding claims as a spray film and / or overpainting existing already permanently painted surfaces and / or for (first) painting on various smooth surfaces such as aluminum, stainless steel, glass, treated leatherette, leather or other non-water-absorbent , ie non-absorbent substrates, as a solid elastic coating varnish for color design and / or for liquid industrial film application on thermal films, calendered as well as cast self-adhesive films for incorporation of security paint, which serve as security seals or temperature indicators; as a protective lacquer for technical applications such as anti-slip as well as water and dirt repellent films, anti-graffiti protective seal. Use of the peel-off lacquer according to one of the preceding claims as a protective film or decorative film which can be removed without residues, the film thickness being 15 μm to 25 μm.

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