EP0888224B1 - Decorative sheet for decoration of three-dimensional substrate surfaces - Google Patents

Abstract

The invention relates to a decorative sheet for decoration of three-dimensional substrate surfaces, said operation involving heating. Said sheet comprises a carrier film which is substantially amorphous, unstretched polyester or polyamide film on which a decorative layer is arranged which is produced from at least one coat of overprinted lacquer forming a decoration precisely adapted.

Description

The invention relates to decorative films for decorating three-dimensional substrate surfaces under heating, which consists of a carrier film and one on top of it arranged decorative layer consist of at least one with the formation of a precisely fitting decor printed lacquer layer is formed.

Such decorative films can generally be used as Transfer foils in the manner of a hot stamping foil, as well as Laminating film to be constructed, when used as Transfer the decorative layer from the carrier film being replaced during the transfer process, while Total laminating films, i.e. both carrier film as well Decorative layer, transferred to the substrate to be decorated become.

Decorative films from a carrier film and a die actual decoration forming the decorative layer are in the various areas used, one of the Areas of application for decorating three-dimensionally designed surfaces. If you have one Want to provide a surface with a decorative film, the Application of the decorative film in the decorative film Be able to deal with the surface irregularities adapt as closely as possible, which is why it is necessary that the decorative film may be sufficient can stretch. This property plays especially with the Decoration of three-dimensional molded parts in presses Role in which, be it with the help of a membrane, be it only with appropriate training Differences in pressure, the decorative film against the surface of the molded part is created. Another area of application is the so-called "insert molding", in which the film is in a Injection mold inserted and then with the formation of the Injection molded part with plastic.

It has already been successful, especially for these purposes to produce suitable decorative foils, however only for those areas of application where there is a certain pattern of the decorative film or the like. Not arrives. This means, for example, if a decorative wooden surface can be imitated supposed to be the "grain" that is created by the decorative layer of the Decorative foil is imitated, possibly considerable May have irregularities.

Such a decorative film is from DE-U-9404567 known, which goes back to the same applicant as the present invention. This document discloses one Decorative film with a backing and one Decorative layer, the decorative layer no has perfectly fitting decor and generally polyester as Carrier layer revealed. It is particularly preferred here a biaxially oriented polyester film. The decoration three-dimensional surfaces takes place in this document no mention.

WO92 / 05030 is a decorative film for decoration known three-dimensional surfaces, the carrier film from an unstretched polyethylene terephthalate film. However, this document discloses only one throughout trained decoration layer, which on different Were manufactured and applied to the substrate can. A reference to a fitting decoration of a three-dimensional surface with a corresponding trained decoration pattern is this document also not to be removed.

The invention is based on the object, a To create decorative film that is especially for the Decoration of finely structured, three-dimensional Substrate surfaces is suitable, and in addition Decorative layer of existing, precisely fitting decor when applied the decorative film on the three-dimensional substrate is not changed or is changed in a precisely predetermined manner, so that when using a decorative film according to the Invention becomes possible, finely structured, three-dimensional Substrate surfaces flawless and with an exact to decorate predetermined patterns.

Surprisingly, it has now been shown that this task can be solved in an extremely simple manner by a decorative film according to claim 1.

Decorative films according to the invention with an amorphous, have unstretched polyamide or polyester film as a carrier especially for the specially intended areas of application the advantage that they can be deformed very strongly, and even at relatively low temperatures. In addition, polyester films are common is very resistant to the usual solvents. Another advantage of the proposed according to the invention Carrier film is its comparatively low price.

So far, have been successful for comparable areas PVC carrier films used. However, these are in view on the environmental problems that arise during disposal questionable. The use of commercially available PE or PP films comes as a carrier film for the purposes of the invention not considered, because such films are not sufficiently deformed, especially not already with comparatively low temperature.

It is generally known that films made of amorphous, unstretched polyester or polyamide can deform strongly at low temperatures. This one Properties and the initially strong shrinking behavior such films when heated, however, make them unsuitable appear when it comes to having a perfectly fitting decor to print an appropriate varnish. During the run through the printing press and especially when drying the Lacquer layer can not be avoided that appropriate train is exerted on the carrier film, still its warming can be prevented. As a result, must the expert fear that the originally printed Decor when passing through the printing press considerable Undergoes changes and loses its accuracy of fit.

The inventor's merit in the present case is well, to have realized that these problems with skillful Guiding the carrier film during the printing process and appropriate training of the decor can be prevented can and also using the itself as inappropriate film from amorphous, unstretched Polyester or polyamide for the intended purposes have excellent suitable decorative foils produced.

Especially the initially strong shrinking behavior of the Backing film when heated must even be considered a privilege be because it causes the decorative film or in particular their carrier film during transmission a structured surface even at relatively low Temperatures (from approx. 80 ° C) and very low Working pressures almost completely at any one designed surface, whereby, as experiments shown have even grooves with a width of less than 1 mm be decorated accordingly with the decorative film can. In this context, the almost plays completely missing tendency of unstretched Film after the deformation play a significant role, whereby it is guaranteed that the decorative film, in particular at Use as laminating film, after deformation and while cooling properly on the decorated Surface adheres without the tendency to stick for example, from narrow grooves or the like. withdraw. The initially strong shrinkage behavior of the carrier films according to The invention leads especially with steep parts Crash edges to a much lower wrinkling in the Compared to previously used PVC supports, but also much lower molded part receptacles are used can, which means cost savings.

The resistance of the carrier film to usually in paints or surface coatings used solvents and aqueous systems offers the Advantage of using a wide range of paints can be, e.g. is also possible, in itself predetermined degree of gloss of the carrier film (this is in the generally slightly matt and semi-transparent) by a corresponding intermediate layer of paint the respective To design needs accordingly.

In summary, it can be said that the use an unstretched, amorphous polyester, polyamide or Polyamide copolymer film as a carrier film Decorative films offer a variety of advantages. Nevertheless, so far has been with regard to the low mechanical stability and the strong shrinking behavior Use of such films as carrier films for Decorative films that fit in a printing process are decorated, considered impossible. The merit it is the inventor's, despite these supposed problems the suitability of non-stretched, amorphous films as carrier film for the decorative foils examined and found to to have.

For most areas of application it has proven to be advantageously shown if the carrier film has a thickness from about 20 to 100 microns.

To achieve sufficiently mechanically strong decorations it is further provided that the decorative layer at least one the precisely fitting decor-forming decorative lacquer layer and one these in use after application to the Comprises protective lacquer layer covering the substrate surface, the protective lacquer layer, for example, accordingly high mechanical strength or UV light resistance may have.

It can also be useful if the decorative layer at least one that forms the perfect fitting decor Decorative lacquer layer and one in use after application the substrate surface under the decorative lacquer layer, covering the entire surface of the colored lacquer layer, whereby further design options open up.

According to the invention is an adhesive layer for Fixing provided on the substrate surface. By appropriate choice of adhesive layer can take into account Art and surface of the substrate to be decorated become.

It is further provided according to the invention that for Use the decorative film as a heat transfer film Decorative layer between the carrier film and the adhesive layer is arranged, in such a case appropriate between the decorative layer and the carrier film Removal layer is provided, which is the detachment of the Carrier film after the application of the decorative layer on the Relieved substrate.

A heat transfer film according to the invention is useful constructed such that successively on the carrier film - if available - the release layer, the Protective lacquer layer, the decorative lacquer layer, the Colored lacquer layer and the adhesive layer are arranged.

Fig. 1

eine Wärme-Transferfolie.

Further features, details and advantages of the invention will become apparent from the following description of a preferred embodiment with reference to the drawing. A partial section of the corresponding decorative film is shown schematically, the thickness ratios of the individual layers not being shown to scale. It shows:

Fig. 1

a heat transfer film.

The heat transfer film shown in Fig. 1 includes one Carrier film 1, on which a release layer 2, e.g. a Wax layer, a total of 3 decorative layer is set.

The carrier film 1 is, according to the invention an essentially amorphous, unstretched polyester film, which has a thickness of 20 to 100 µm, depending on the Field of use.

Amorphous, unstretched have proven particularly suitable Polyethylene terephthalate films have been proven Softening range is between 70 ° C and 80 ° C. The Elongation is when the Softening temperature greater than 300%. The Tension model drops when the Softening temperature below 500 N.

In addition to polyester, especially polyethylene terephthalate films also have amorphous, undrawn polyamide films and Films made from copolymers based on polyamide Softening temperatures of less than 120 ° C and one Elongation of over 300% when this is exceeded Temperature proved to be suitable.

The decorative layer 3 of the exemplary embodiment in FIG. 1 then includes a release layer 2 transparent protective lacquer layer 4. On this Protective lacquer layer 4 is one, for example a grain forming decorative lacquer layer 5 printed with a precise fit. Following the decorative lacquer layer 5 is one continuous color lacquer layer 6 is provided. The last Layer of the decorative layer 3 forms an adhesive layer 7, for example from a heat-activated adhesive.

The layer thicknesses in the heat transfer film of FIG. 1 are as follows: Peel layer 0.01 to 0.50 µm Protective coating 1 to 5 µm Decorative lacquer layer 0.1 to 2 µm Color coat 3 to 25 µm Adhesive layer 5 to 20 µm.

The heat transfer film according to FIG. 1 is used either by means of a membrane or simply by appropriate pressure difference - using the Heat transfer film itself as a membrane - against that appropriately structured surface of a substrate pressed, the decorative layer 3 facing the substrate and by means of the adhesive layer 7 on the substrate surface is set. After applying the heat transfer film completely to the substrate surface and optionally certain cooling then the carrier film 1 of the Decorative layer 3 and thus removed from the substrate surface, which is facilitated by the presence of the release layer 2 becomes. If necessary, the release layer 2 to be dispensed with if the protective lacquer layer 4 is so is composed that it is correspondingly easy from the surface of the carrier film 1 can solve.

Of course, the structure of the decorative layer 3 compared to the embodiment of FIG. 1 be different. In particular, under certain circumstances the colored lacquer layer 6 or the protective lacquer layer 4 to be dispensed with. However, it is essential that a correspondingly printed decorative lacquer layer 5 is available. The adhesive layer 7 can also under certain circumstances omitted if either the colored lacquer layer 6 or the most distant position from the carrier film 1 Decorative layer 3 are sufficiently sticky to adhere the decorative layer 3 on the substrate surface ensure or if the adhesive layer before Applying the decorative layer 3 to the substrate, for example by spraying or the like.

The layers forming the decorative layer 3 can be composed, for example, as follows: Peel layer 2 Parts by weight Water, deionized 740 Polyvinyl alcohol (degree of hydrolysis 98.4 ± 0.4 mol%) 10th Ethyl alcohol 250 Protective lacquer layer 4 Methyl ethyl ketone 400 toluene 230 Cyclohexanone 100 Methyl methacrylate (Tg = 105 ° C) 195 Polyethylene wax (mp = 140 ° C) 75 Decorative lacquer layer (grain) 5 Methyl ethyl ketone 270 Ethyl acetate 175 Butyl acetate 200 Methyl n-butyl methacrylate (TG = 80 ° C) 86 Methyl methacrylate (TG = 35 ° C) 114 High molecular weight dispersing additive (40%, amine number: 20) 50 Pigment Brown 23 45 Pigment Yellow 93 40 Pigment Black 7 20th Color coat (back up) 6 Methyl ethyl ketone 250 toluene 135 Ethyl acetate 80 Methyl-n-butyl methacrylate (Tg = 80 ° C) 145 Methyl methacrylate copolymer (Tg = 86 ° C) 60 Highly disperse silica (particle size 10µm) 5 High molecular dispersion additive (40%, amine number 20) 15 Titanium dioxide (TiO ₂ content 94%, d = 4.1 g / cm ³ ) 250 Iron oxide yellow (Pigment Yellow 42, d = 4.1 g / cm ³ ) 60 Adhesive layer 7 Ethyl alcohol 180 toluene 300 Thermoplastic polyamide resin (softening point: 140 ° C) 80 Ketone-formaldehyde resin (Ext .: 85 ° C) 60 Ethyl methacrylate copolymer (Tg = 50 ° C) 60 Finely divided silica (particle size 10µm) 5 High molecular weight dispersion additive (40%, amine number 20) 15 Titanium dioxide (TiO ² content 94%, d = 4.1 g / cm ³ ) 250 Iron oxide yellow (Pigment Yellow 42, d = 4.1 g / cm ³ ) 50

Of course, the compositions of the different layers of paint depending on the special Areas of use are varied, particularly if necessary, individual layers can be dispensed with can. The thickness of the layers depends on the particular one Application area and must above all take this into account to what extent stretching the film and thus parallel thinning of the layers at Application to the three-dimensional surface of the Substrate is expected.

Claims (7)

1. Decoration film in the manner of a thermal transfer film for decorating three-dimensional substrate surfaces with heating, comprising a carrier film and disposed atop it a decorative coating of at least one coat of coating material, which is printed on sectorially so as to form an in-register decoration, the said carrier film (1) being an essentially amorphous, unoriented polyester film, polyamide film or polyamide copolymer film, an adhesive coat (7) being provided for fixing to the substrate surface, and the decorative coat (3) being disposed between the carrier film (1) and the adhesive coat (7).
2. Decoration film according to Claim 1, characterized in that the carrier film (1) is polyethylene terephthalate film.
3. Decoration film according to Claim 1 or 2, characterized in that the carrier film (1) has a thickness of from about 20 to 100 µm.
4. Decoration film according to one of the preceding claims, characterized in that the decorative coat (3) comprises at least one sectoral coat (5) of decorative coating material, which forms the in-register decoration, and a coat (4) of protective coating material which covers the coat (5) in use following application to the substrate surface.
5. Decoration film according to one of the preceding claims, characterized in that the decorative coat (3) comprises at least one sectoral coat (5) of decorative coating material, which forms the in-register decoration, and comprises a coat (6) of coloured coating material which is applied over the whole area and which in use following application to the substrate surface is situated below the coat (5) of decorative coating material.
6. Decoration film according to one of the preceding claims, characterized in that a detachment coat (2) is provided between the decorative coat (3) and the carrier film (1).
7. Decoration film according to one of the preceding claims, characterized in that - where present - the detachment coat (2), the coat (4) of protective coating material, the sectoral coat (5) of decorative coating material, the coat (6) of coloured coating material and the adhesive coat (7) are disposed in succession on the carrier film (1).

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