FR3133154A1 - Process for decorating surfaces, and decorative film obtained by such a process - Google Patents

Abstract

TITLE: Process for decorating surfaces, and decorative film obtained by such a process. The present invention relates to a method for decorating surfaces comprising the following steps: a step of projecting ink (11) onto a first face (22) of a decorative film (2) made of a polymer material, a step of exposure of said first face (22) to ultraviolet radiation (12), until the ink hardens, a step of hot crushing (13) of the decorative film (2), at a temperature above 130° vs. The invention also relates to a decorative film (2) obtained by this process. Abstract Figure: Figure 1

Description

Process for decorating surfaces, and decorative film obtained by such a process. Field of the invention

The present invention relates to a process for decorating surfaces, making it possible to represent a pattern on surfaces of all types.

It also relates to decorative films made of polymer materials obtained by such processes, which make it possible to carry out surface decoration.

Prior art

Surface decoration consists of modifying the visual appearance of a surface, by adding, for example, ornamentation, patterns, or even writing.

We know different surface decoration processes.

According to some of these processes, the surfaces are decorated by gluing a personalized decorative film, which can for example be self-adhesive.

Once installed on their supports, these collage decorations are not very resistant to mechanical abrasion, light and bad weather. Glue decorations tend to crease and/or crumble quickly over time. Their lifespans are therefore generally short due to these multiple external attacks.

In other processes, decorations are directly printed on surfaces by digital printing processes, during which the media to be decorated pass through a digital printer which reproduces images from graphic data files.

After printing, the decorations are usually fixed and protected from light by layers of varnish, penetrating fixatives and hardeners.

Such treatments add additional steps to surface decoration. However, it appears that they often do not offer sufficiently effective resistance to decorations. In particular, they generally do not offer very effective resistance to abrasions.
Objectives of the invention

The present invention aims to overcome these drawbacks of the prior art.

In particular, an objective of the invention is to propose a surface decoration process which makes it possible to give the decorations advantageous resistance properties, compared to the surface decoration processes of the prior art.

A particular objective of the invention is to provide a surface decoration film having good adhesion to the surfaces to be decorated on which it is stuck.

Yet another objective of the invention is to provide a surface decoration film suitable for all types of supports.

A particular objective of the invention is to provide surface decorations that are particularly resistant to bending, abrasion and light.

• une étape de projection d’encre sur une première face d’un film décoratif constitué d’un matériau polymère,
• une étape d’exposition de la première face à un rayonnement ultraviolet, jusqu’au durcissement de l’encre,
• une étape d’écrasement à chaud du film décoratif, à une température supérieure à 130°C.

These objectives, as well as others which will appear more clearly later, are achieved using a surface decoration process which comprises, according to the invention, the following steps:

• a step of projecting ink onto a first face of a decorative film made of a polymer material,
• a step of exposing the first face to ultraviolet radiation, until the ink hardens,
• a step of hot crushing of the decorative film, at a temperature above 130°C.

Hot crushing of the decorative film, after its printing with an ink hardened by ultraviolet radiation, makes it possible to penetrate the ink into the decorative film and to make the printing of this film extremely resistant to wear, and in particular to abrasion. The resulting film, which can be stuck to any type of surface that needs to be personalized, therefore offers a very solid and durable decoration.

Advantageously, the decorative film is made up at least partially, during the ink projection step, of a monomer material which is not entirely polymerized, this material being capable of being polymerized under the effect of heat and/or ultraviolet radiation.

The fact that the material constituting the film is not entirely polymerized makes it easier for the ink to penetrate the film. After printing, the decorative film made of a monomeric material is advantageously polymerized during the step of exposing the decorative film to ultraviolet radiation or during the step of hot crushing this decorative film against the support to decorate. This polymerization reinforces the mechanical characteristics of the film.

Preferably, the decorative film has a thickness of between 20 and 200 micrometers.

Such a thickness allows the decorative film to maintain a certain flexibility, thus making it easier to adhere to multiple supports.

Advantageously, the surface decoration method comprises a step of gluing a second face of the decorative film, opposite the first face, against a support to be decorated.

Advantageously, the hot crushing step and the gluing step are carried out simultaneously, by crushing the decorative film against the support to be decorated, a layer of glue being provided between the decorative film and the support to be decorated.

Preferably, the hot crushing step is carried out by calendering between two cylinders, at least one of the cylinders being heated to a temperature above 130°.

Such a temperature increases the adhesion of the decorative film to the support to be decorated. It should be noted that the more the temperature is increased, the more the adhesion of the decorative film to the support to be decorated is improved.

Advantageously, the hot crushing step is carried out by simultaneous calendering of the support to be decorated and the decorative film, the second face of the decorative film being pressed against the support, and the first face of the decorative film being pressed against one of the cylinders which are heated to a temperature above 130°.

Advantageously, at least one of the cylinders is heated to a temperature of between 150 and 180°C.

Advantageously, during the hot crushing step, the decorative film is exposed to a temperature above 130° for a period of between 10 and 40 seconds.

The invention also relates to a decorative film obtained by a process as described above.
List of Figures

• La est une représentation schématique des étapes du procédé de décoration de surfaces selon un mode de réalisation de l’invention.
• La est une représentation schématique d’un film décoratif mis en œuvre dans le procédé de décoration de surfaces de la .
• La est une vue de détail d’une portion du film décoratif de la .
• La est une représentation schématique de l’étape d’écrasement à chaud du film décoratif, dans le procédé de décoration de surfaces de la .
• La est une représentation schématique d’un support décoré par un film décoratif après la mise en œuvre du procédé de décoration de surfaces de la .
• La est une vue de détail d’une portion du support et du film décoratif de la .

Description détaillée de modes de réalisation de l’inventionThe invention will be better understood on reading the following description of preferred embodiments, given as a simple figurative and non-limiting example, and accompanied by the figures among which:

• There is a schematic representation of the steps of the surface decoration process according to one embodiment of the invention.
• There is a schematic representation of a decorative film used in the process of decorating surfaces of the .
• There is a detailed view of a portion of the decorative film of the .
• There is a schematic representation of the hot crushing step of the decorative film, in the process of decorating surfaces of the .
• There is a schematic representation of a support decorated with a decorative film after the implementation of the surface decoration process of the .
• There is a detailed view of a portion of the support and the decorative film of the .

Detailed description of embodiments of the invention

There represents the main stages of a surface decoration process according to one embodiment of the invention.

• une étape de projection d’encre 11 qui consiste à projeter de l’encre sur une surface d’un film décoratif dans son état monomère afin de le décorer,
• une étape d’exposition à un rayonnement ultraviolet 12 de l’encre, et
• une étape d’écrasement à chaud 13 du film décoratif, de préférence contre la surface à décorer.

1. Le film décoratif
   1. Définition générale

According to this embodiment, the method comprises:

• an ink projection step 11 which consists of projecting ink onto a surface of a decorative film in its monomeric state in order to decorate it,
• a step of exposing the ink to ultraviolet radiation 12, and
• a hot crushing step 13 of the decorative film, preferably against the surface to be decorated.

1. Decorative film
   1. General definition

This process uses a decorative film made of a polymer material. The term "polymer material" is designated indifferently in the present description to fully polymerized polymer materials, such as polyurethane, polyester, polyamide or acrylic or the precursors of these polymer materials, or so-called monomeric materials, suitable for to be transformed, by polymerization, into polymer materials such as polyurethane, polyester, polyamide or acrylic.

In the preferred embodiment represented by the figures, this decorative film 2 is made of so-called “monomer” material, which comprises precursors of polymer materials which are not polymerized or which are only weakly polymerized. Such a monomer film can be polymerized, in particular under the effect of heat and/or ultraviolet radiation, to form a polymerized polymer film.

The decorative film 2 is an elastic film and has a low thickness. For example, the thickness of this decorative film 2 is between 20 and 200 micrometers. Such finesse and flexibility offers the possibility of affixing the decorative film 2 to very diverse surfaces.
The material forming this film is advantageously thermoplastic, and can be made more malleable when heated. Furthermore, this material retains, after its complete polymerization, a certain flexibility. Such a film of thermoplastic polyurethane material is for example marketed by the company “Protechnic Thermoplast, 68700 Cernay – France”, under the reference “7GA” (https://www.protechnic.fr/wp-content/uploads/2021/06 /catalogue-thermo-ENG-200204.pdf).
b. Two sides

There represents, schematically, a decorative film 2 made of monomeric material which is implemented in a process according to a preferred embodiment of the invention. A portion 20 of this decorative film 2 is represented in more detail by the . This decorative film 2 has two distinct sides.

The first face of the decorative film 2, subsequently called “rear face 21”, is intended to adhere to the support to be decorated. The second face of the decorative film 2, subsequently called “front face 22”, is intended to be printed, and to form the future exterior face of the surface to be decorated.
vs. Optional Features

According to a preferred embodiment, the rear face 21 can be covered with glue, over its entire surface, even before printing the front face 22 of the decorative film 2. According to another possible embodiment, the face rear 21 is only covered with glue later, for example when the decorative film 2 is placed on the support to be decorated 4.

When the rear face is covered with glue, it can, for the film printing stages, be pressed against a support sheet which may be made of plastic. The decorative film 1 is, however, detached from this support sheet before being stuck to the surface to be decorated.
2. Decorative film printing

The front face of the decorative film 2 can be decorated by printing, in particular by implementing a conventional printing process during which inks are projected onto its surface, before being solidified by exposure to ultraviolet radiation.
has. Impression

The first ink projection step 11 of the process consists of projecting an ink onto the front face 22 of the decorative film 2. This ink projection can be carried out by a printer of a known type.

According to an advantageous embodiment, the ink used for printing the decoration on the decorative film 2 is a special ink for ultraviolet printing in a neutral medium. Such ink generally includes pigments, polymers, monomers and UV ink radical initiators, and does not include water or solvent.

The front face 22 of the decorative film 2 is then covered with a layer of ink 221 which forms a pattern or extra thickness ornamentation. This layer of ink 221 is however not solidified upon its projection on the decorative film 2, but must be solidified subsequently.
b. Exposure to ultraviolet radiation

Preferably, the ink used for printing the decorative film 2 is capable of being solidified by polymerization, when exposed to ultraviolet radiation. The second step of exposure to ultraviolet radiation 12 of the process consists of projecting ultraviolet radiation onto the front face 22 of the decorative film 2.

This treatment with ultraviolet radiation causes the solidification of the ink layer 221, in a manner well known to those skilled in the art. As represented by the , this ink layer 221 of hardened ink, representing the desired pattern, thus forms a slight colored extra thickness on the front face 22 of the decorative film 2. This layer of hardened ink, similar to an ink film polymerized on the surface of the decorative film 2 can, despite the solidification of the ink, have a certain flexibility.

In addition to causing the polymerization, and therefore the solidification, of the inks projected on the surface, the exposure of the front face 22 to ultraviolet radiation can also, advantageously, cause a partial polymerization of the decorative film 2, when this film consists of a monomeric material which is not fully polymerized, and the crosslinking of the polymers constituting the decorative film 2.

Such a modification of the surface of the decorative film 2 can have several advantages. Thus, the presence of the polymerized ink layer on the front face 22 of the decorative wire 2, and the start of polymerization of the decorative film 2 which may result from its exposure to ultraviolet radiation makes it possible to improve the heat resistance of this decorative film 22. Thus, it appeared that the front surface 22 of this decorative film 2 having undergone such treatment is capable of withstanding exposure to temperatures of the order of 130°C to 180°C without deforming, then that the same decorative film, having not been printed or subjected to ultraviolet radiation, risks deforming or puncturing when subjected to a temperature above 120°C.
3. Hot crushing

The third hot crushing step 13 of the process consists of pressing the front face 22 of the decorative film between two supporting surfaces, at least one of which is heated.
has. Film placement

According to a particularly advantageous embodiment, this third hot crushing step 13 can be implemented by pressing or hot crushing the decorative film 2 against the support to be decorated 4. This third hot crushing step 13 can then be used to hot-glue the decorative film 2 to the support.

There represents, schematically, a preferred embodiment of the invention in which the hot crushing is carried out in the form of calendering, and is used to plate and stick the rear face 21 of the decorative film 2 on a support to decorate 4. The support to be decorated 4 is, in the embodiment shown, a flexible support such as fabric, leather, etc. The method of the invention can, however, also be implemented, without difficulty, on a support of another type, for example a rigid support.

The decorative film 2 is inserted, at the same time as the support to be decorated 4, between two cylinders 31 and 32 of a calender 3, which are juxtaposed one to the other, so as to leave the space just necessary for accommodate the decorative film 2 and the support to be decorated 4. During this passage through the calender 3, the front face 22 of the decorative film 2 is pressed against the cylinder 32, while the rear face 21 is pressed against the support to be decorated 4 , which is itself pressed against the cylinder 31. More precisely, the rear face 41 of the support to be decorated 4 is placed against the cylinder 31, while the front face 42, which is the face to be decorated, is oriented towards the cylinder 32. Thus, the front face 42 of the support to be decorated 4 is gradually attached to the rear face 21 of the decorative film 2.

This step of crushing the decorative film 2 makes it possible to exert pressure on this film. The pressure exerted can however be of relatively low intensity, for example of the order of 10 N/cm². Compression at an intensity greater than 1 N/cm² may even prove sufficient in certain cases.
b. Heating

According to the invention, the step of crushing the printed decorative film 2 is carried out hot. For this, the cylinder 32 is heated, preferably to a temperature above 130°C, and more preferably to a temperature between 150°C and 180°C.

According to one embodiment of the invention, the decorative film 2 is placed against the heated cylinder 32 for a period of between 10 and 40 seconds. Those skilled in the art will be able to define, depending on the characteristics of the support to be decorated 4 and the decorative film 2 used (and in particular the thickness of the decorative film 2 and the material constituting it) the duration and the temperature of the heating allowing it to obtain an optimal result of polymerization of the decorative film and bonding of the decorative film 2 to the support to be decorated 4.
vs. Diffusion of pigments

The heat produced by the cylinder 32 makes it possible, in association with the crushing of the decorative film 2, to cause the pigments of the ink layer 221 to penetrate within this decorative film 2. Thus, the ink layer 221 which was initially placed in extra thickness on the front face 22 of the decorative film 2, penetrates into the heart of this decorative film, and becomes inseparable from it.
d. Film polymerization

During this hot crushing step 13, the heating emitted by the cylinder 32 also causes the polymerization of the decorative film 2, when this film is made up of a monomer material which is not fully polymerized. The decorative film 2 can thus be, at the end of this step, in a fully polymerized state. This polymerization makes the decorative film 2 much stronger, and in particular more resistant to abrasion and wear. The decorative film 2, in its polymerized state, is less flexible than in its monomeric state. However, it retains good flexibility, allowing it to be easily combined with soft surfaces such as textile surfaces.
e. Film/support adhesion

In the preferred embodiment shown on the , the hot calendering step is used to bond the decorative film 2 to the support to be decorated 4. For this, glue can be provided from the manufacture of the decorative film 2, the glue is then placed on the rear face 21 of the decorative film 2, before hot calendering, and thus ensures effective bonding.

Preferably, the glue chosen reacts to heat, so that the hot calendering carried out by the cylinder 32, by heating the glue and crushing the decorative film 2 against the support, ensures effective bonding of the decorative film 2 against the support to be decorated 4.

In this embodiment, the adhesion of the decorative film 2 to the support to be decorated 4 and the polymerization of this decorative film 2, described previously, take place simultaneously during the hot calendering step.
f. Graining

Advantageously, when the support to be decorated 4 has an irregular surface, the hot crushing of the decorative film 2 thereon allows the decorative film 2 to match this irregular surface. Thus, the front face 22 of the decorative film 2 can, once attached to the support to be decorated 4, present a graining, obtained without any additional step. For example, a decorative film placed on a fabric can thus match the weave of the fabric, which produces a graining on the front face 22 of the decorative film 2.
g. Other embodiments

According to another possible embodiment, the step of hot calendering the decorative film 2 can be carried out independently of the step of gluing the film to the support to be decorated 4. It is thus possible that the decorative film 2 is glued to the support before hot calendering. In this case, the decorative film 2 is crushed hot after bonding.

According to another embodiment, the decorative film 2 is crushed hot, for example by calendering, without being pressed against the support to be decorated. In this case, the decorative film 2 is stuck against the support to be decorated 4 after hot calendering, that is to say after the decorative film 2 has been polymerized.

In the embodiment shown in a figure, the hot crushing of the decorative film 2 is carried out by a calender. However, it remains possible to carry out this hot crushing with any other type of equipment, for example with a press.
4. The result
has. Film obtained

This process described above results in the formation of a decorative film made of polymer material, printed, flexible and solid. This printed decorative film thus proves to be resistant to various attacks such as abrasion, bending or light.

There represents, schematically, a support 4 decorated with a decorative film 2, in its polymerized state, according to one embodiment of the invention. A portion 30 of this decorative film 2 stuck on the support to be decorated 4 is represented in more detail by the .

After hot calendering of the decorative film 2 against the support to be decorated, the rear face 21 of the decorative polymer film 2 finds itself stuck against the support to be decorated 4 while the front face 22 of this decorative film 2 is oriented in the opposite direction .

Heating the decorative film 2, during hot crushing, causes the polymerization of the monomer material initially constituting this decorative film 2. This polymerization has the effect of reinforcing the mechanical characteristics of the material constituting this decorative film, which means that the decorative film 2 obtained is particularly resistant.

Due to the hot crushing caused by calendering, the ink layer 221 is inserted inside the decorative film 2. Thus, as shown in , the ink layer 221 no longer forms an extra thickness above the decorative film 2, but has penetrated inside the thickness of this decorative film 2. Due to this penetration, the ink is surrounded by the polymer constituting the decorative film 2, which protects it and reduces the risk of abrasion and discoloration on the surface of the decoration.
b. Types of decorated supports

This surface decoration process makes it possible to decorate a wide variety of supports such as luggage items, textiles, bodywork, etc. The supports to be decorated can be flexible or rigid, and of different thicknesses.

This process offers the possibility of obtaining decorated supports which can withstand mechanical and thermal stress, exposure to light and bad weather.

Furthermore, this surface decoration process can be implemented using printing techniques in which the inks do not include solvents. The implementation of this process can therefore be more respectful of the environment by avoiding any release of pollutants, engravings or even heavy metals.

Claims (10)

Surface decoration process comprising the following steps:

• A step of projecting ink (11) onto a first face (22) of a decorative film (2) made of a polymer material,
• a step of exposing said first face (22) to ultraviolet radiation (12), until said ink hardens,
• a hot crushing step (13) of said decorative film (2), at a temperature above 130°C.

Surface decoration method according to the preceding claim, characterized in that said decorative film (2) is constituted at least partially, during said ink projection step (11), of a monomeric material which is not fully polymerized, this material being capable of being polymerized under the effect of heat and/or ultraviolet radiation. Surface decoration method according to any one of the preceding claims, characterized in that said decorative film (2) has a thickness of between 20 and 200 micrometers. Surface decoration method according to any one of the preceding claims, characterized in that it comprises a step of gluing a second face (21) of said decorative film (2), opposite said first face (22), against a support to decorate (4). Surface decoration method according to the preceding claim, characterized in that said hot crushing step (13) and said gluing step are carried out simultaneously, by crushing said decorative film (2) against said support to be decorated (4), a layer of glue being provided between said decorative film (2) and said support to be decorated (4). Surface decoration method according to any one of the preceding claims, characterized in that said hot crushing step (13) is carried out by calendering between two cylinders (31, 32), at least one of said cylinders (32 ) being heated to a temperature above 130°. Surface decoration method according to claims 4 and 5, characterized in that said hot crushing step (13) is carried out by simultaneous calendering of the support to be decorated (4) and the decorative film (2), said second face of said decorative film (2) being pressed against said support to be decorated (4), and said first face (22) of said decorative film (2) being pressed against one of said cylinders (32) which is heated to a temperature greater than 130° . Surface decoration method according to any one of claims 5 and 6, characterized in that at least one of said cylinders (32) is heated to a temperature between 150 and 180°C. Surface decoration method according to any one of the preceding claims, characterized in that, during said hot crushing step (13), said decorative film (2) is exposed to a temperature greater than 130° for a duration between 10 and 40 seconds. Decorative film (2) of polymer material obtained by the process according to any one of the preceding claims.