The present invention relates to a process and a machine to coat at least one surface of an article and an article thus obtained.

CONTEXT OF THE INVENTION

In the finishing of wooden conglomerates the surface treatment with decorative paper impregnated with melamine in a press at temperatures of about 200°C and with simultaneous application of pressure of at least 25 Kg/cm ² is known. This methodology requires the availability of a production chain (present only in some industrialized countries) which comprises specialized companies able to produce large quantities of printing stock of colored paper, gravure printing large quantities of paper of a single design, impregnating in a water suspension bath of modified melamine, wringing and drying in hot air at 110-130 °C with consequential energy expenditure. It is clear that this type of methodology is complex, expensive and also requires an elevated expenditure of energy. In this regard, note that small production batches are currently very uneconomic (for this reason there is a need to produce in large quantities) .

Another disadvantage is the fact that it is not possible to execute such a finishing in low density conglomerates as these would collapse under the effect of the required pressure. Consequently, the conglomerate wood industry is often forced to use toxic recycled wood due to the shortage of raw materials. The toxicity increases with each new recycling.

Moreover, this finishing technique cannot be use with surfaces different from wooden conglomerates surfaces, such as sheets of plastic composite materials, honeycomb panels, fiber cement, plasterboard, etc.. Another known system for the finishing of panels is to apply on the raw panel small metered amounts of about 30 g/m ² of pigmented UV paint (i.e. able to solidify when exposed to UV radiation) , apply pressure and, simultaneously, irradiate with UV radiation. Note that, as mentioned, it is usually not possible to apply more than 30 g/m ² of pigmented UV paint, as larger quantities would imply increased thickness and, therefore, the impossibility that UV radiation would reach the inner layers. Therefore, to obtain greater thicknesses (and therefore a better quality coating - usually at least 150 g/m ² ) the procedure must be repeated several times in succession (applications and radiation) . Usually, the layer of paint thus obtained is sanded and subjected to other processes.

This type of methodology (which for example, is described in the patent EP1587637B1 and EP1363770B1) has several disadvantages, among which are cited: high costs and processing times (e.g. due to the necessity to repeat the same steps several times) ; the necessity to apply substantially transparent paint (color paint - i.e. pigmented - would not allow the passage of UV radiation into the inner layers) ; the necessity to use transparent pressure tapes (also in this case to allow the passage of UV radiation) resulting in increased costs and increased imprecision in application (note that transparent material tapes, which may be used, are mainly made of deformable materials - contributing to the deformation, again for transparency reasons, also the fact of not being able to use tapes with high thickness) ; and a high risk to workers health, which workers could suffer eye damage resulting from the use of UV radiation.

Aim of the present invention is to provide a machine, a process and an article, which allow to at least partially overcome the limits of the state of the art and can, at the same time, be easily and economically produced. SUMMARY

According to the present invention, a machine, a process and an article are provided according to what is recited in the independent claims that follow and, preferably, in any of the claims directly or indirectly depending from the independent claims . BRIEF DESCRIPTION OF FIGURES

The invention is described as follows with reference to the annexed drawings, which illustrate non-limiting embodiment examples, in which:

- Figure 1 is a schematic side view of a device made in accordance with the present invention;

- Figure 2 is a schematic side view of a further embodiment of a device made in accordance with the present invention;

- Figure 3 is a perspective view with details removed for clarity purposes of another embodiment of a device made in accordance with the present invention; and

Figure 4 is a schematic side view of an additional embodiment of a device made in accordance with the present invention. EMBODIMENTS OF THE INVENTION

In Figure 1, with 1 a machine for at least partially coating an article 2 is indicated as a whole. The machine 1 comprises a conveyor system CS for moving forward the article 2 along a treatment path P; a deposition assembly 3 to deposit a thermosetting liquid paint, which (comprises a thermosetting resin and) is free of organic solvents, on at least a surface of the article 2; and an application assembly 4, which is arranged downstream of the deposition assembly 3 along the treatment path P, and comprises at least one element 5 in a flexible and elastic material, which is adapted to press the thermosetting liquid paint on the surface and transferring, simultaneously, heat to the paint itself (in order to at least partially harden it) .

In particular, the element 5 is in silicone. According to some embodiments, the silicone has the following formula:

where n is an integer greater than 1, in particular greater than 4 (advantageously greater than 10) , each R is chosen, independently from the others in the group consisting of: methyl, ethyl, propyl. Advantageously, the silicone is PDMS.

The treatment path P comprises a segment T, in the area of which the deposition assembly 3 and the application assembly 4 are arranged.

The machine 1 also comprises a heater assembly 6 for heating the element 5 at a temperature greater than 90°C (in particular, greater than 100°C) and less than about 260°C (in particular, less than about 230°C) . Advantageously, the element 5 is heated to a temperature up to 210°C (in particular, up to 200°C) .

According to certain embodiments, the element 5 comprises elevations and/or depressions . In this way, the element 5 is capable of imparting an embossment upon the paint.

The deposition assembly 3 comprises at least one (in this specific case two) spreader 7. The (each) spreader 7 is adapted for transferring the contact thermosetting liquid paint by a pair of rollers 8.

According to various embodiments (for example, as shown in Figures 2 and 3) , the deposition assembly 3 comprises at least one extruder 9, which is adapted for transferring the thermosetting liquid paint upon the surface of article 2. The application assembly 4 comprises a tape 10 (Figure 1 and 2) closed upon itself and an actuating device 11 to move the tape 10 along a path Pi (also closed upon itself) . The tape 10 comprises the element 5. In the illustrated embodiment, the tape 10 is the element 5.

Advantageously, the tape 10 comprises at least one reinforcement element for reducing the deformability of the tape 10 itself. In particular, the tape 10 comprises (internally or on the surface) a canvas (or mesh) .

The canvas (or mesh) is, typically, substantially inextensible . In particular, the mesh (or canvas) comprises (more specifically is of) metal and/or Kevlar. Advantageously, the tape 10 comprises a toothed belt. More in particular, the tape 10 comprises two toothed belts, each of which is arranged at a corresponding edge of the tape 10 itself . For illustrative purposes, silicone sleeves ( flexographic sleeves) produced by Tecnoitalxa® can be used as tapes 10.

More specifically, at least one reinforcement element is associated with the element 5 for reducing the deformability of the element 5 itself.

In the present case, the actuating device 11 comprises two end rollers 12, at least one of which being motorized, and a return roller 13, which is arranged offset with respect to the end rollers 12. In use, the tape 10 runs around the end rollers 12 and the return roller 13.

The path Pi has a work segment Tl, in the area of which the element 5 comes into contact with article 2 (and therefore with the paint) . In use, the element 5 accompanies in contact the article 2 (and therefore the paint) along the segment Tl . In other words, along the segment T and Tl the article 2 and the element 5, respectively, move at the same speed. The path Pi also has a return segment T2 (which is arranged on the opposite side of the end rollers 12 with respect to the segment Tl) . More specifically, the segment Tl extends between the end rollers 12; the segment T2 extends between each end roller 12 and the return roller 13.

The segment Tl and the segment T are parallel (and facing each other) .

The application assembly 4 also comprises a pressure device 14 adapted to impart pressure on the element 5. In particular, the device 14 comprises an articulated chain 15 (rolling shutter) , which is coupled with the tape 10 in the area of the segment T of the path Pi. In use, the chain 15 runs around the end rollers 12.

The device 14 also comprises a guide 16 along which the chain 15 slides in correspondence to the segment T. Specifically, the chain 15 is made of metal.

According to different and not illustrated embodiments, the pressure device 14 comprises an intake unit adapted for the aspiration of the element 5 (and also the tape 10) towards the article 2. More precisely, the pressure device is in accordance with that described in patent EP1587637B1.

As shown in Figure 1, the heater assembly 6 comprises at least one source 17 (more precisely, a plurality of sources) of infrared radiation. Advantageously, the heater assembly is arranged outside of the segment Tl . In particular, the (each) source 17 is arranged outside of the segment Tl . More precisely, the (each) source 17 is arranged in the area of the segment T2. In accordance with the shown embodiment, the heater assembly 6 comprises a plurality of infrared lamps 17.

According to non-illustrated embodiments, the heater assembly 6 comprises a fluidic circuit for heating at least one of the rollers 12 and 13 by way of oil.

The machine 1 also comprises at least one printing assembly 18 for applying a given pattern (using ink) on the paint (at least partially hardened) . According to the embodiments illustrated in Figures from 1 to 3 , the printing assembly 18 comprises one or more inkjet printing devices 19 (advantageously digital) . The printing assembly 18 also comprises at least one UV radiation source 20, which (arranged downstream of the printing device 19) is adapted for stabilizing (drying) the ink deposited on the paint.

For example, the printing assembly 18 can imprint a pattern simulating wood grain.

The thermosetting liquid paint comprises at least one pigment. Thermosetting liquid paints are known and easily manufactured by industries in the field. In particular, thermosetting liquid paints comprise at least one resin (thermosetting) and (possibly) a thermal activator (crosslinker) .

According to certain embodiments, the thermosetting liquid paint is made according to one (or more) of the following indications :

epoxy type resins in combination with "Dicyandiamide" as an activator (which induces crosslinking at 130-135°C) ;

polyester resins in combination with epoxy resin containing "Dicyandiamide" as an activator (which induces crosslinking at 130-135°C) ;

polyester resins in combination with "Primid XL552" (which induces crosslinking at 200°C) as an activator; polyester resins in combination with "Araldite PT 910" (chemical name l-chloro-2, 3-epoxy propane synonymous to Epichlorohydrin) as an activator (which induces crosslinking from 100°C to 200°C) ;

water-base acrylic resins (resins of this type on the market first lose water, then crosslink more or less quickly depending on the given temperature, in which case a passivation -evaporation of the water- is induced before submitting them to the heated element 5) .

An example of a usable paint is " ESABOND DP 35" (of a polyurethane type) Lamberti SpA, ss. Bergamo-Crema No. 591 - 20050 Zanica IT. In the embodiment of Figure 1, the article 2 is a panel. More precisely, the article 2 is a panel in a material composed mainly of cellulose and/or lignin. In other words, at least 50% of the article 2 is the sum of cellulose and lignin. More in particular, the substantially inert material comprises (more specifically is) wood (or a material similar to wood) .

As can be easily seen from Figure 1, the article 2 is coated both from above and below. In this case, we have deposition assemblies 3, and application assemblies 4 and (printing assemblies 18) both above and below the path P (and therefore the article 2 as well) .

The embodiment shown in Figure 2 is very similar to the embodiment of Figure 1 and differs from it due to the following elements:

the deposition assembly 3 comprises the extruder 9;

the article 2 is a tape; and

the article 2 is only upperly coated. Advantageously, the machine 1 of Figure 2 also comprises a device D adapted for providing a "crown" type treatment on the tape 2. The tape can be a low-pressure laminate or a decorative paper or a thin metal etc.

In Figure 3 is shown an embodiment according to which the article 2 is a panel (e.g. in wooden material as defined above) and an edge of that panel is coated.

In this case, the deposition assembly 3 comprises the extruder 9, which has its own head (end) shaped so as to induce a given form to an outer surface of the paint.

The application assembly 4 comprises a plurality of rollers 22 arranged at the work segment Tl and positioned (and oriented) in accordance with a specific profile of the outer surface of the paint.

The embodiment illustrated in Figure 4 differs from the embodiment of Figure 1 for the fact of comprising (downstream of the application assembly 4) an additional deposition assembly 3', an additional application assembly 4' (arranged downstream to deposition assembly 3 ' ) and an additional heater assembly 6'. What has been said relatively to the deposition assembly 3, to the application assembly 4 and to the heater assembly 6 shall apply "mutatis mutandis" (with necessary changes) to the deposition assembly 3', the application assembly 4 ' and the heater assembly 6 ¹ , respectively (regardless that corresponding assemblies can still be different) . Usually, the deposition assembly 3 ' apply an additional paint similar to the paint applied by the deposition assembly 3. Advantageously, the additional coating is substantially transparent . Furthermore, in the machine of Figure 4, the printing assembly 18 comprises a plurality (in particular, four - each for one color) of printing belts 23 (in itself known - for example, sold by Tecnoitalia®) . The printing belts 23 are provided with small pockets that hold the ink coming from a respective hopper 24 releasing it upon the articles 2. Each deposition assembly 3 and 3 ' comprises a respective deposition tape 24 (which works similarly to printing belts 23) .

In use, with particular (but not limitative, and/or exclusive) reference to the machine of Figure 1: during a deposition step, the thermosetting liquid paint, which (comprises a thermosetting resin and) is free of organic solvents, is deposited on said surface; during a heating step, the element 5 (in particular the tape 10) is heated to a temperature less than about 260°C (in particular, less than about 230°C) during an application step, the element 5 (in particular, the tape 10) compresses the paint onto the surface simultaneously transferring heat to the paint itself. The application step is subsequent to the deposition step (and heating) and leads to the hardening (at least partial) of the thermosetting liquid paint. In particular, the element 5 is a membrane (in silicone) .

Advantageously, the heating of element 5 is by way of infrared radiation. The element 5 is heated to a temperature greater than about 90°C (in particular, greater than about 100°C) .

The element 5 (i.e. the tape 10) is moved along the path Pi closed upon itself.

During the application step, the article 2 is conveyed along the treatment path P. During the application, at least a portion of the element 5 comes into contact with the thermosetting liquid paint (and accompanies the article 2) in the area of the segment T. In other words, in the area of the work segment Tl the element 5 comes into contact with the thermosetting liquid paint.

The element 5 is heated outside of the segment Tl . In particular, the element 5 is heated just before reaching the segment Tl . More precisely, the element 5 is heated in correspondence to the return segment T2 (which is upstream of the work segment, with respect to the movement direction of the tape 10) . During the application step, the paint is heated to a temperature from about 90°C (more precisely, from about 100°C) to about 210°C. Advantageously, during application step, the paint is heated to a temperature up to about 200°C (in particular, up to about 180°C) .

It is important to note that, in some cases, it is preferable to stay below 200°C (in particular, less than 180°C) . Advantageously, in these cases, the paint is heated to a temperature less than 150°C (in particular less than 130°C) .

According to certain embodiments, a printing step is also provided, during which at least one ink is applied upon the paint so as to formulate a pattern. The printing step is (at least partially) after the application step.

According to the embodiment of Figure 4, an additional deposition step is also provided, during which additional thermosetting liquid paint, which comprises a thermosetting resin and is free of organic solvents, is deposited (by the deposition assembly 3') on said paint. In particular, although the paint and the additional paint may be identical or different, the above given definition of the paint applies also to the additional paint.

Advantageously, the additional paint is substantially transparent. Advantageously, the additional paint comprises corundum and/or zirconium silicate (as transparent as possible) . In this way, the resistance to abrasion is increased.

During an additional heating step, an additional element 5 (in silicone) is heated to a temperature (greater than 90°C) and less than 260°C.

During an additional application step, which is at least partially successive to the deposition step, the additional element 5 compresses the additional thermosetting liquid paint upon the surface, simultaneously transferring heat to the additional paint.

The additional deposition step is (at least partially) after the application step. In particular, the additional deposition step is (at least partially) after the printing step (thus protecting the print) .

According to certain embodiments, the element 5 embosses the paint .

In certain cases (see Figure 3), the deposition step (and any additional deposition step) by means of a contoured element (in particular, a head contoured by the extruder 9) so as to define a profile determined by the outer surface of the paint.

During the application step the element 5 runs on a plurality of oriented rollers 22 in accordance with a profile determined by the outer surface of the paint.

The subject matter of the present invention has significant advantages with respect to the state of the art. Cited among others are:

- the possibility of using low pressures (resulting in cost savings and reduction of toxicity of materials) ;

- the possibility of applying relatively thick layers of paint with a single treatment (this allows quality improvement also for any additional embossing) ;

- the possibility of using also heavily pigmented paints (i.e. non-transparent ) ;

- the possibility of using non-transparent tapes 10;

- the non-use (or lesser use) of UV radiation harmful to eyes and skin of the workers and pollutants (during procedure, toxic and polluting ozone can form) ;

- the possibility of treating panels from two sides;

- increase in the hardness of the surface, whereas a surface treated normally would have a Mohs hardness of about 3, the surface treated as described above (since the hardening - cross linking - of the paint is in the substantial absence of oxygen) has a Mohs hardness of about 5-6;

- The ability to use elements 5 (or tapes 10) that are scarcely deformable.

With reference to the latter point, we stress that this leads, for example, to an increased accuracy of embossing. This is particularly useful when the embossment and pattern produced by the printing assembly 18 must match (e.g. when desiring to reproduce a wood effect) .

Unless explicitly stated otherwise, the content of the documents (articles, books, patent applications, etc..) cited in this text is wholly recalled herein. In particular, the mentioned documents are incorporated herein by reference.

Additional features of the present invention will result from the following description of an example for illustrative purpose only and not limiting the implementation of the microfluidic system 1.

Example

The product "ESABOND DP 35" (of the company, Lamberti SpA, strada statale Bergamo-Crema No.591 - 20050 Zanica IT - of an aqueous polyurethane dispersion type) , was coated and set with hot air at 110°C and immediately subjected to a contact of 2 seconds to the silicone membrane whose surface temperature was raised to 200°C. A thermal strip placed in the paint has reported the achievement of the temperature needed for polymerization, which was indicated by the co. Lamberti to be at 130-135°C, upon which, in fact, the temperature of 132- 138°C remained impressed.