NL1019786C2 - Paint composition for a removable decorative layer. - Google Patents

Description

Paint composition for a removable decorative layer

The invention relates to a paint composition for a removable decorative paint layer on a non-porous substrate and to a method for applying such a paint composition as a removable decorative layer.

During special occasions such as international football competitions or national holidays, national colors are used to enhance the festivities. For example, on the internet website www.metalak.nl/pers/pers1.htm and in the magazine Autovisie®, 46th volume, edition 15, 21 July 2001, page 30, car paints are described with which a car can be provided with a temporary coat of paint , for example, to be sprayed in the national color of a country competition. The car paints described in these publications are starch-based compositions. The disadvantage of such starch-based paints is that they are not water resistant. The paint layer was washed off after a rain shower or wash. The water disappears with the paint residues into the environment. The special paint must also be sprayed in a professional spray booth for car repair paints. The paint can therefore not be applied in a simple manner by an untrained user.

The object of the invention is a paint composition which can be applied in a simple manner to a non-porous substrate as a water-resistant decorative layer which can be removed in a simple manner. It must be possible to remove the paint layer 25 without aids that can damage the underlying layer. The invention also has for its object to provide a method for applying a removable decorative layer to a non-porous substrate.

The object of the invention is achieved with a paint composition for a removable decorative layer on a non-porous substrate, characterized in that the paint composition is a pigmented lacquer based on a polymeric binder, which forms a film whose internal cohesion is greater than the adhesion to the substrate.

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Due to the ratio between adhesion and cohesion, such a paint composition can be used to provide an easily removable, water-resistant decorative layer.

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It is true that U.S. Pat. Nos. 4,562,226 and 6,124,044 disclose strippable lacquers for temporarily applying removable protective layers to, for example, passenger cars. However, these stripping slices are only used for temporarily protecting the substrate in relatively thick, wear-resistant layers. Although such lacquers have hitherto had no decorative function and are used for industrial applications, it has been found that strippable lacquers provided with pigments in a certain color are particularly suitable for applying an easily removable decoration by an untrained person.

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The lower the glass transition temperature of the applied paint layer, the easier it is to remove the paint layer at once. In contrast to the lacquer layer of US 6,124,044, which is intended as a wear-resistant, hard protective layer, the lacquer layer according to the present invention preferably has a glass transition temperature Tg that is lower than 19 ° C, preferably below 13 ° C, most preferably below 9 ° C.

In order to obtain the desired glass transition temperature for the lacquer layer, the paint composition preferably comprises a polymeric binder with a Tg lower than 19 ° C, preferably below 13 ° C, most preferably below 9 ° C.

The flexibility of the paint layer also has a favorable influence on the strippability of the paint layer. Therefore, use is preferably made of a paint composition which gives a paint layer which after drying has an elastic modulus of less than 20 MPa, preferably less than 15 MPa. Optimal results are obtained if the modulus of elasticity of the paint layer is less than 11 MPa.

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Suitable binders are, for example, copolymers of vinyl acetate. Particularly suitable are copolymers of vinyl acetate and dialkyl maleate. The equivalent ratio of vinyl acetate: dialkyl maleate monomer in the co-5 polymer is usually between 1: 1 and 10: 1. The alkyl groups of the dialkyl maleate, independently of one another, usually have 1 to 8 carbon atoms. Preferably, the dialkyl maleate is dibutyl maleate. An example of a suitable commercially available binder is Mowilith® DM 2H from Clariant GmbH, Frankfurt.

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The paint composition can contain organic solvents or be water-based. Waterborne paint compositions are preferred because they are suitable for more substrates and, for example, are less likely to attack the paint layer of a passenger car. Moreover, the health risks for the user and the environmental impact of water-based paint compositions are smaller. If the paint composition is water-based, it may contain up to 25% by weight, based on binder, of organic solvent as a co-solvent, for example glycols.

Suitable methods of preparation for the binder for aqueous paint compositions are aqueous emulsion polymerization as described in WO 00/39181, or polymerization in solvent followed by dissipation in water.

To obtain the desired color, the paint composition contains one or more pigments, for example orange pigment. The pigments can be organic or inorganic. The pigment content is generally between 1 to 20% by weight, calculated on binder. The paint composition may also contain dyes that are wholly or partially soluble in the paint composition.

The paint composition can contain additives such as, for example, fillers, flow agents, emulsifiers, anti-foaming agents, rheology control agents, anti-oxidants, UV stabilizers, etc.

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The paint composition can be prepared with various solids contents, which are generally between 20% and 80%, but preferably between 30% and 65%, depending on the application method chosen.

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The paint composition according to the invention can be applied in any known manner, preferably in a manner that can be easily carried out by an untrained person, for example by rolling or brushing.

Examples of suitable non-porous substrates are pre-treated metals, pre-treated wood, plastics and glass. Suitable substrates are also other layers of paint, such as present on transport vehicles, for example passenger cars, bicycles, trains, trucks and buses.

The applied paint composition can be dried at ambient temperature, more specifically at a temperature of -10-50 ° C. No special provisions are needed to let the paint dry.

As mentioned above, the paint compositions according to the invention are suitable for applying a decoration. The decoration can comprise the entire outer surface of, for example, the body of a passenger car, or it can be applied to only a part of the substrate, for example a text such as "Just Married".

When the user wants to remove the temporary paint layer again, the paint layer according to the invention can be stripped manually in a simple manner. Stripping the paint is even easier when the film is heated, for example after treatment with warm water.

The invention will be further elucidated with reference to the following exemplary embodiments. In the examples, the E-modulus is determined according to ISO 527-1 and 527-3 on the basis of paint films stripped from a glass substrate. The glass transition temperature Tg is determined by means of:

Differential Scanning Calorimetry (DSC), as described in Encyclopedia of Polymer Science and Engineering, Volume 4, pages 482-519, 1986 (Wiley Interscience). Percentages in the examples are weight percentages based on the total weight of the composition.

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Example 1

A paint composition was prepared based on a water-borne dispersion of a copolymer of vinyl acetate and dibutyl maleate with a Tg of 5 ° C (Mowilith® DM 2H). The paint contained 3% of a white pigment (titanium dioxide), 0.8% monoethylene glycol as a co-solvent and 0.5% surfactants.

The paint was applied to a glass substrate. The thickness of the film was 143 micrometers. After drying, the film could easily be stripped off the substrate as a whole. The modulus of elasticity was equal to E = 11 MPa. The Tg of the dried paint film was 5 ° C.

Example 2 A second paint composition was prepared based on Mowilith® DM 2H. The paint contained 4% of a yellow pigment (Hansa® yellow), 4% monoethylene glycol as a co-solvent and 1% surfactants.

The paint was applied to a glass substrate. The thickness of the film was 151 microns. After drying, the film could easily be stripped off the substrate as a whole. The modulus of elasticity was equal to E = 9 MPa. The Tg of the dried paint film was 4 ° C.

Claims (9)

A paint composition for a removable, decorative layer on a non-porous substrate, characterized in that the paint composition is a pigmented lacquer that forms a film whose internal cohesion is greater than the adhesion to the substrate. 2. Paint composition according to claim 1, characterized in that the paint composition contains a binder whose glass transition temperature is lower than 19 ° C, preferably lower than 13 ° C. Paint composition according to claim 2, characterized in that the glass transition temperature after application and drying of a paint film is lower than 19 ° C, preferably lower than 13 ° C. 15 Paint composition according to one of the preceding claims, characterized in that the paint composition forms a film with an elastic modulus E that is lower than 20 MPa, preferably lower than 15 MPa. A paint composition according to any one of the preceding claims, wherein the binder is a copolymer, a vinyl or acrylate copolymer. The paint composition according to claim 5, wherein the binder is a copolymer of vinyl acetate and dialkyl maleate, preferably dibutyl maleate. 25 A paint composition according to any one of the preceding claims, wherein the paint composition is a physically drying water-based latex. 8. Method for applying a removable decoration to a non-porous substrate, the decoration consisting of a paint layer whose internal cohesion is greater than the adhesion with the substrate. 1 n 1 o λ r. ' ► Method according to claim 8, wherein the paint layer is applied to a transport vehicle, such as a bus or passenger car.