FR2868735A1 - METHOD AND INSTALLATION OF PRINTING THERMOPLASTIC MATERIAL SLABS TO REALIZE REPORTED FLOOR - Google Patents

Abstract

A method for printing thermoplastic floor tiles involves printing tiles in a horizontal position with UV-drying ink, drying the ink (after application in the case of direct printing or before in the case of indirect printing), then applying a protective coating and drying the coating. A method for printing and protecting the print on thermoplastic floor tiles, involves (a) positioning at least one prefabricated tile (1) so that at least one of the sides (5, 5') to be printed is horizontal, (b) applying at least one layer (6) of UV-drying ink to at least part of that surface (5, 5'), drying being effected after application to the surface for a direct print or before application for an indirect print, (c) applying protective coating(s) (9) to the top layer of ink and (d) drying the protective coating (9). An independent claim is also included for apparatus for printing thermoplastic floor tiles, comprising a means of supporting tiles in a horizontal position (especially a table, tray or conveyor belt), a system for depositing layer(s) of UV-drying ink (e.g. a direct printing station for silk-screen printing or micro-drop deposition, or an indirect printing station for thermal transfer processes), a system for applying a protective coating (especially a varnishing station) and a UV-drying unit, preferably comprising UV lamps emitting in the 220-440 range.

Description

The invention relates to a method for printing and protecting

  printing thermoplastic slabs adapted to form at least a portion of a reported soil.

  The invention also relates to an installation for printing and the protection of this printing, by such a method, of slabs of thermoplastic material.

  Such slabs are used to form a ground floor placed on an existing floor or surface, for example a concrete screed, a floor, a tile. This soil is intended to replace this surface. We know, especially in industries, shops and public or collective premises, such reported soil. The slabs usually used have various colors and, optionally, a face having a non-smooth appearance, for example grains of rice, grained or glittery. These slabs can also have their upper face evoking a type of coating, for example wood, marble or other decor. Such characteristics are achieved during the manufacture of the slabs and are made from the material constituting the slab. As a result, it is not possible to change the appearance of such slabs. If one wants to change the appearance of the upper face of the slabs, for example for informational purposes by putting security pictograms or for a decorative purpose or advertising, it is generally carried out by the application of stickers or cuts practiced in the slab to insert elements of shapes and / or various colors. In all cases, these solutions are not easy to implement and are not satisfactory. Indeed, in the case of stickers, repeated passages of people and / or gear on the slabs quickly lead to wear and tear of the latter. The realization of cuts in the slabs and the insertion of other elements in the latter, allow to achieve only certain markings. Moreover, the induced costs do not allow unit production or in small series.

  It is to these drawbacks that the invention more particularly intends to remedy by proposing a method of printing and protecting the printing of slabs of thermoplastic material, flexible to use, adaptable to all types of marking, scalable. In addition, the slabs obtained by this method are resistant to wear and are of a low production cost for custom production, customizable, especially in small series.

  To this end, the subject of the invention is a process for printing and protecting the printing of thermoplastic material slabs adapted to form at least a part of an attached soil, characterized in that it comprises steps consisting of to: a) positioning, after its manufacture, at least one slab so that at least one of the faces to be printed is substantially in a horizontal plane, b) deposit on at least a portion of said face, at least one layer, in at least one pass, of an ultraviolet-radiation drying ink, the drying being performed after the deposition of the ink on the face for direct printing or prior to the deposition of the ink on the face for printing indirect.

  c) applying on the upper layer of ink, at least one layer of a protective coating, d) drying said protective coating layer.

  Thanks to the method of the invention, an impression is obtained on all shapes and sizes of slabs. This impression has a high wear resistance and can be performed both unit and mass production for advantageous production costs, while being easily customizable.

  According to advantageous but not obligatory aspects of the invention, such a method may incorporate one or more of the following features: In step d), the drying of the protective coating layer is carried out by ultraviolet radiation.

  - The protective coating layer is a varnish, especially a powder coating based on mixed epoxy-polyester resins. Alternatively, the protective coating layer is a polyurethane-based liquid varnish.

  - Prior to step d), the liquefaction or gelling of the powder coating is carried out at a temperature between 110 and 150 C, so as to form a uniform layer of varnish.

  During step a), several slabs are juxtaposed, their faces to be printed lying in the same plane, so that the sum of the unit areas of the slabs is substantially equal to the surface to be printed. During their juxtaposition, the slabs are held mutually in position by connecting members, including mortise / tenon type members.

  After step b) and before step c), during step e), the slabs are separated from each other.

  - Before step b) or in step a), during step f), the slabs are degreased prior to the application of the first ink layer.

  - Before step c) or after step d), is carried out, in step g), cooling slabs, in particular by placing them in a stream of air.

  After step d) or after step g), at a new step a), at least one slab already printed is repositioned to perform another printing on the same slab.

  Before step b), during a step h), an undercoat is applied to the face to be printed. Advantageously, this underlayer is of a neutral hue with respect to each printed color, in particular the underlayer is opacifying, for example white.

  Thermosetting polymer slabs, in particular PVC, with a Shore A hardness of from 65 to 100, and advantageously from 85 to 95, are used.

  The invention also relates to an installation for implementing a method of printing slabs of thermoplastic material and, in particular, an installation comprising: - means for supporting at least one slab so that At least one of the faces to be printed is in a substantially horizontal plane, in particular a table, a tray or a conveyor belt, means for depositing at least one UV-curing ink layer in at least one pass, in particular a direct printing station by screen printing or deposition of microdroplets or an indirect printing station by thermal transfer, means for depositing a protective coating, in particular a station for depositing a varnish, drying means by ultraviolet radiation, in particular lamps of wavelength emitted between 220 and 440 nanometers.

  Advantageously, the installation comprises a deposit station for a powder varnish associated with a varnish preheating means, in particular an infrared radiation liquefaction station comprising lamps with an emitted wavelength of between 1.1 and 2.6 micrometers.

  Advantageously, such an installation also comprises means for drying at least one layer of ink by ultraviolet radiation when the ink layer is deposited by direct printing. Such an installation may comprise at least one cooling means, in particular a blower disposed at the outlet of at least one of the drying means.

  The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of a printing method according to the invention, given solely for the purpose of by way of example and with reference to the accompanying drawings in which: - Figure 1 is a general view of a slab, as used in the printing process according to the invention, before printing, - Figure 2 is a general view of a portion of a reported floor, formed of several slabs juxtaposed and printed according to the method according to the invention and - Figure 3 is a diagram of an installation for the implementation of a method printing according to the invention.

  The slab 1, shown in Figure 1, is a thermoplastic polymer slab and, in particular, a PVC slab. This slab is semi rigid. In this case, its Shore A hardness is generally between 85 and 95. Slabs having a Shore A hardness between 65 and 100 can, in practice, be used. Typically, slabs, of the slab type 1, are adapted to be placed on an existing floor or surface, as long as this floor or surface is stable, relatively flat and rigid. It may be, for example, a concrete screed, a floor, a tile or any other known floor. The slabs 1 can be fixed to this floor, for example by gluing, screwing or using fasteners known per se slabs 1 can also be placed on the ground without being secured to the latter.

  These slabs 1 may be equipped, on at least a part of their periphery, connecting members 2 to connect together and maintain juxtaposed. Thus, as shown in Figure 2, several slabs 1 juxtaposed form part of a reported floor. The connecting members 2 comprise several lugs 3, generally T-shaped and evenly spaced on the periphery of the slabs 1. These connecting members 2 are such that a lug 3 of a slab 1 is adapted to be housed in the space 4 located between two lugs 3 of another slab 1 adjacent. When it is desired to print one or more faces 5 of these slabs 1, including, possibly, the connecting members 2, the face 5 to be printed is positioned in a substantially horizontal plane P, as shown in FIG. for example, the slab 1 on a table or conveyor belt. Depending on the area of the surface to be printed, one or more slabs 1 are used. In this case, the slabs 1 are assembled and held in position by virtue of their respective connecting members 2. During assembly, it is ensured that all the faces 5 to be printed are in the same horizontal plane P, these faces 5 must all be accessible simultaneously for the subsequent steps of the method.

  The slabs 1 are thus printed, unitarily or assembled flat, that is to say in a position similar to that they once in place on the original floor.

  If necessary, the surfaces to be printed are degreased, the purpose of the degreasing being to remove solid and / or liquid soils, in particular the fatty residues resulting from the manufacture of slabs 1.

  The method makes it possible to print the faces 5 of the slab 1 whatever the appearance of these faces. Thus, it is possible to print smooth or non-smooth faces, especially granular faces, made of rice grains, spangled or granulated.

  After positioning the slab or slabs 1 on a working support, a first step of printing is performed by depositing on this or these faces 5 a layer 6 of one or more inks. Advantageously, each ink is drying, that is to say polymerization or crosslinking, by ultraviolet rays. These inks are in liquid or powder form.

  This ink or inks is deposited by techniques relating, for example, to direct printing, in particular to digital printing. In this case, ink microdroplets are projected on the faces 5 to be printed. Depending on whether monochrome or quadrichrome printing is desired, and depending on the number of available printheads, the number of passes required of the ink deposition system is performed above the print side. This technique is known as drop on demand.

  One can also use, always in direct printing, the technique of screens of silk or serigraphy. In this case, the ink is applied, dyed by hue, using screens or stencils, on the areas to be printed, with the same hue, of the faces 5.

  The actual fixing of the ink layer on the faces 5, whatever the technique employed, is obtained by drying the ink under ultraviolet rays. This passage under UV rays allows drying of the ink layer 6 at a sufficiently high temperature and for a time long enough to ensure the drying of the ink but short enough not to reach the melting point of the constituent material of the ink. slabs 1. This drying technique allows the use, for the slabs 1, of semi-rigid thermoplastic material with a low melting temperature, close to 180 C. Alternatively, an indirect printing technique may be used, for example example, by heat transfer. In this case, the ink is carried by a so-called transfer paper then sublimated, namely heated between 120 and 150 C for 15 to 50 seconds under a pressure of between 2 and 5 bar. During this sublimation, the ink passes directly from the solid state to the gaseous state and enters the constituent material of the slab 1 at the faces 5 to be printed. The ink is dried by ultraviolet radiation when it is deposited on the transfer paper before being transferred to the print side. This drying solidifies the ink to then perform sublimation.

  This step can be followed, if necessary, a cooling slabs 1 for example by passing them in a stream of air at a temperature below or close to room temperature. This cooling makes it possible to preserve the dimensional stability of the slabs. Advantageously, the slabs pass under a blower 8 of refrigerated air or not.

  The next step is to apply at least one layer of protective coating on the ink layer 6 to preserve the impression of the slab 1.

  This application of protective coating can be done on the slabs 1 assembled or on slabs 1 separated from each other. This variant allows to perform in two different places, the printing and application of the protective coating while occupying a minimum of space. The coating or protective varnish can be applied directly after printing for example, without cooling slabs or after cooling slabs. The time interval AT between the end of printing and the application of the protective coating is variable.

  In all cases, the nature of slabs 1, inks and protective coating are adapted to be chemically compatible.

  It is also possible to rearrange the slabs 1 differently so as, for example, to obtain, when the protective coating is applied, a working surface with an area greater or smaller than the printing surface. For example, several slabs 1 printed together during different printing can be grouped together in order to obtain a larger surface for applying the protective coating and thus to optimize the process. Just make sure that the printed faces 5 slabs 1 associated or neighboring are all located in the same plane. It is thus possible to have supports bearing several adjacent rows of slabs 1.

  During the implementation of this coating step, a protective coating layer is applied to the printed face 5, advantageously a powdered, thermosetting varnish 9, for example a varnish based on mixed epoxy and polyester or polyurethane resins. The application of this layer of varnish 9 is, for example, using an electrostatic gun either triboelectric type or corona type. A protective film of the varnish 9 with a thickness of between 20 and 70 microns and, advantageously, between 35 and 55 microns is thus deposited.

  This powder varnish 9 undergoes, at first, a preheating to liquefy or gel. This preheating is done by techniques known per se and, in particular, under infrared radiation. The infrared lamps used have a wavelength of between 1.1 and 2.6 micrometers. In this case, the lamps used are carbon-emitting, with a power of about 40 watts per centimeter. This preheating is carried out at a temperature generally between 110 and 150 C and for a time between 30 and 120 seconds.

  The liquefaction can also be carried out by passing the slabs in an oven or an oven, by adjusting the temperature and the time of passage in the oven or oven.

  Preheating makes it possible to liquefy and evenly distribute the varnish 9 on the face 5 to be printed. The actual drying is then carried out by passing the layer of varnish 9 thus liquefied under ultraviolet radiation for a few seconds at about 120 ° C. in order to crosslink the varnish 9. This crosslinking, or polymerization, of the varnish takes place without the ink or the material constituting the slab 1. Advantageously, mercury or mercury / gallium lamps 7 are used, the wavelengths of which, in the ultraviolet, are between 220 and 440 nanometers. It is also possible, at the end of drying and before storing or handling the slabs 1, to cool them by passing through an air stream 8 refrigerated or not.

  Alternatively, a liquid varnish based on polyurethane can be used. This varnish, monocomponent, is polymerizable by ultraviolet radiation.

  In the case of a solvent-based one-component varnish, the drying, in the absence of a hardener, the latter being replaced by photoinitiators, is carried out by solvent evaporation and by ultraviolet radiation in a manner similar to that described previously.

  If the one-component varnish is solvent-free or has low solubility, its viscosity is such that it is necessary to heat it to 40 ° C. to 50 ° C. in order to thin it out so as to be able to spread it prior to ultraviolet drying. The reheating is done, during the application of the varnish, by techniques known per se, for example by heating coils.

  If the varnish is of the mixed type, that is to say comprising a hardener and photoinitiators, the ultraviolet radiation makes it possible to obtain only partial but rapid drying. A complementary resin / hardener crosslinking is necessary to obtain the complete drying of the varnish within about 48 hours.

  Such a printing process can be repeated several times. On a slab 1 printed and varnished, it is possible to make another printing. In this case, if necessary, a slight degreasing of the slab is carried out. It can also be printed directly on the varnish layer 9 without degreasing.

  This method is applicable to print indifferently an upper face 5 'or a 5' lower face of the slab. When it is desired to print the lower face 5 'of the slab 1, that is to say the face of the slab in contact with the existing floor, the same method is used, but here the ink forms, in negative, the pattern to print. The protective layer of the printing may be of a thickness different from that previously used, this protective layer not having to be in contact with the outside.

  The varnish 9 serves only to preserve the impression of the contact with the ground on which the slab is placed, the protection against wear due to repeated passages on the slab does not need to be. The protection of the visible part of the printing is done by the slab 1 itself. Such a method is particularly suitable for use in the framework of slabs 1 made of transparent or translucent thermoplastic material.

  It is also possible, in the case of an impression or prior to the first ink deposition step, to apply to the face 5, 5 'which it is desired to print, a sub-layer based on a monochrome ink. This underlay must be of a neutral hue not altering the colors of the print. Advantageously, an opacifying sub-layer, for example white, is used which makes it possible to have a neutral background, or primer, for printing. This sub-layer is particularly useful when the initial color of the slab is not in agreement with the colors of the print and may change the perception of the latter. This sub-layer, once applied, is for example crosslinked under ultraviolet radiation.

  Of course, in the case of slabs 1 transparent or translucent, it does not apply tinted undercoat prior to the deposition of the ink, this sub-layer does not allow the vision of printing. On the other hand, it is possible to apply, on the face 5 ', a transparent undercoat, in particular a layer of varnish.

  As a variant, it is possible to limit the printing of the slabs 1 to a part of the surface of the slabs 1, for example to the exclusion of the connecting members 2.

2868735 14

Claims (18)

  A method of printing and protecting the printing of thermoplastic material slabs adapted to form at least a portion of an attached soil, characterized in that it comprises steps of: a) positioning, subsequent to its manufacturing, at least one slab (1) so that at least one of the faces (5, 5 ') to be printed is substantially in a horizontal plane, b) deposit on at least a portion of said face (5, 5 '), at least one layer (6), in at least one pass, of an ultraviolet radiation drying ink, said drying being performed subsequent to the deposition of the ink on said face (5, 5') for printing direct or prior to the deposition of the ink on the said face (5, 5 ') for indirect printing, c) applying on the upper layer (6) of ink, at least one layer (9) of a protective coating d) drying said protective coating layer (9).   2. Method according to claim 1, characterized in that during step d), the drying of the layer (9) protective coating is carried out by ultraviolet radiation.   3. Method according to claim 1 or 2, characterized in that said protective coating layer is a varnish (9), especially a powder lacquer based on mixed epoxy-polyester resins.   4. Method according to claim 1 or 2, characterized in that said coating layer (9) is a polyurethane-based liquid varnish.   5. Method according to claim 3, characterized in that, before É in step d), the liquefaction or gelling (10) of said powder varnish (9) is carried out at a temperature of between 110 and 150 ° C., to form an even layer of varnish.   6. Method according to one of the preceding claims, characterized in that, in step a), several slabs (1) are juxtaposed, their faces (5, 5 ') to be printed lying in the same plane (P). ), so that the sum of the unit areas of said slabs (1) is substantially equal to the surface to be printed.   7. Method according to claim 6, characterized in that, during their juxtaposition, said slabs (1) are mutually held in position by connecting members (2), including members (3) of the type mortise / tenon.   8. Method according to one of claims 6 or 7, characterized in that, after step b) and before step c), in a step e), said slabs (1) are separated from each other. others.   9. Method according to one of the preceding claims, characterized in that before step b) or step a), is degreased in a step f), the slabs (1) prior to the application of the first layer (6) of ink.   10. Method according to one of the preceding claims, characterized in that before step c) or after step d), is carried out, in a step g), cooling slabs, in particular by placing them in a stream of air (8).   11. The method of claim 10, characterized in that, after step d) or after step g), is repositioned, in a new step a), at least one slab (1) already printed to perform another impression on the same slab.   12. Method according to one of the preceding claims, characterized in that, before step b) is applied, in a step h), a sub-layer on said face (5, 5 ') to be printed.   13. The method of claim 12, characterized in that said sub-layer is of a neutral shade vis-à-vis each printed color, in particular the sub-layer is opacifying, for example white.   14. Process according to one of the preceding claims, characterized in that slabs (1) made of thermoplastic polymer, in particular PVC, with a Shore A hardness of 65 to 100 and, advantageously, from 85 to 95, are used.   15. Installation for printing slabs of thermoplastic material, characterized in that it comprises: - means for supporting at least one slab (1) so that at least one of the faces (5, 5 ') ) to be printed in a substantially horizontal plane, in particular a table, a tray or a conveyor belt, - means for depositing at least one layer (6) of ultraviolet-radiation drying ink in at least one pass, in particular a printing station, for example direct printing by screen printing or deposition of microdroplets or an indirect printing station by thermal transfer, means for depositing a protective coating, in particular a deposit station for a varnish (9 ), ultraviolet radiation drying means, including lamps (7) of wavelengths emitted between 220 and 440 nanometers.   16. Installation according to claim 15, characterized in that it comprises a deposition station of a varnish (9) powder associated with a preheating means of the varnish, in particular an infrared radiation liquefaction station comprising lamps (10). ) of a transmitted wavelength of between 1.1 and 2.6 microns.   17. Installation according to claim 15, characterized in that it also comprises means for drying at least one layer (6) of ink by ultraviolet radiation when said layer (6) is deposited by direct printing.   18. Installation according to one of claims 15 to 17, characterized in that it comprises, at least one cooling means, in particular a blower (8) disposed at the outlet of at least one drying means (7).