OBJECTS, IN PARTICULAR LIGHTING APPARATUSES, AND LIGHTING APPARATUSES REALIZED WITH SAID METHOD k k k k k

FIELD OF THE INVENTION

The invention relates to a plant and a method for realizing nanomaterial coatings on surfaces of objects, in particular, lighting apparatuses and lighting apparatuses realized with said method.

KNOWN BACKGROUND ART

Various processes are known for applying coatings to the surfaces of the most varied products .

Some known coatings contain nanoparticles, i.e., particles which have one or more external dimensions included in the size range from 1 nm to 100 nm.

For example, coatings containing titanium dioxide (Ti0 ₂ ) nanoparticles are known, capable of photocatalyt ically degrading the polluting agents in water or air purification applications .

However, the greatest disadvantage in the use of titanium dioxide-based photocatalysts is that these are active only if irradiated by a suitable light source having a wavelength in a particular range within the near ultra-violet region (UV-A) (l = 350-400 nm) due to the relatively large "band-gap" energy of the TiCy (E.g. = 3.0-3.2 eV) which only absorbs radiations with a wavelength lower than about 387 nm. Furthermore, it is not always easy to apply nanomaterial coatings, especially on non-planar surfaces and/or on three-dimensional objects. It is therefore an object of the present invention to provide a plant and a method for applying a nanomaterial on surfaces of different materials, including transparent materials such as, for example, glass.

It is another object of the present invention to provide antibacterial properties to the nanomaterial coating.

BRIEF SUMMARY OF THE INVENTION

The present invention, therefore, aims at meeting the above mentioned objects by means of a plant for realizing nanomaterial coatings on surfaces of objects, wherein the plant comprises a plurality of work stations arranged subsequently, among which:

- a station for dry cleaning and activating, with atmospheric plasma, the surfaces to be coated;

- a station for pre-heating the surfaces to be coated;

- a spraying station to coat the surfaces with a nanomaterial coating;

- a pre-heating oven, and

- an oven with multiple stages controlled at different temperatures, and

- a cooling station.

An advantage of the present invention is given by the fact that the described plant allows the application of a nanomaterial coating ("coating") on surfaces of different objects and different materials, in particular, not only on planar surfaces, but also on three- dimensional objects and on materials such as plastic materials, glass, ceramics, cardboard, fabric and, substantially, any other material that may be coated. A further advantage is given by the homogeneity of the application of the nanomaterial, in particular, on transparent surfaces which must be capable of letting the light pass, as in the case of lighting apparatuses provided with photocatalytically activated surfaces .

The high homogeneity of the coating obtained on a support of transparent material is highly advantageous because otherwise the nanomaterial would be clearly visible in light contrast .

The invention further comprises lighting apparatuses comprising a support for one and more luminous elements, wherein the aforesaid luminous elements are associated with internal and/or external light diffusion surfaces, characterized in that the aforesaid internal and/or external light diffusion surfaces are coated with a nanomaterial comprising titanium dioxide (TiCt) or another photocatalyst which may be activated by means of visible light and further comprising silver or other organic or inorganic biocides (Zinc oxide ZnO, Tungsten trioxide W03 Copper Cu, Zinc Zn, etc..) .

This embodiment has the considerable advantages given by the presence of a photocatalyst which may be activated by means of visible light and allows the activation of the nanomaterial in a self-cleaning mode with visible and non-visible light, unlike other TiCt-based products which are instead activated by means of UV radiation.

The addition of silver and other biocides gives the nanomaterial antibacterial and sanitizing properties.

Further features of the invention may be deduced from the dependent claims .

BRIEF DESCRIPTION OF THE FIGURES

Further features and advantages of the invention will become more apparent in the light of the detailed description which follows with the aid of the accompanying drawings in which: - Figure 1 shows a block diagram of a process for realizing nanomaterial coatings on surfaces of objects according to an embodiment of the invention;

- Figure 2 shows a side view of a plant for realizing nanomaterial coatings on surfaces of objects, according to an embodiment of the invention;

- Figure 3 shows a top view of the plant of Figure 2;

- Figure 4 shows a drop of water deposited on a surface treated according to the background art;

- Figure 5 shows a drop of water deposited on a surface treated in accordance with the invention;

- Figure 6 shows an axonometric view of a dry cleaning and activating station which uses atmospheric plasma;

- Figure 7 shows an axonometric view of a pre-heating station according to an embodiment of the invention;

- Figure 8 shows a view of a spraying station to coat the surfaces with a nanomaterial coating according to an embodiment of the invention;

- Figure 9 shows an axonometric view of a portion of a lighting apparatus treated, on the surfaces thereof, with the nanomaterial coating process;

- Figure 10 shows an axonometric view of the entire lighting apparatus of Figure 9;

- Figure 11 shows an axonometric view of a modular component of the lighting apparatus of Figure 10; - Figure 12 shows an axonometric view of a further lighting apparatus treated, on the surfaces thereof, with the nanomaterial coating process;

- Figure 13 shows an axonometric view of a projector treated with a nanomaterial coating;

- Figure 14 shows an axonometric view of an outdoor projector treated with a nanomaterial coating;

- Figure 15 shows an axonometric view of a ceiling light treated with a nanomaterial coating; and

- Figures 16 and 17 show axonometric views of bulbs treated with a nanomaterial coating.

DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

The invention will now be described with an initial reference to Figure 1 where a process for realizing nanomaterial coatings on surfaces of objects according to an embodiment of the invention is diagrammatically shown.

In particular, the process comprises a plurality of steps to be carried out subsequently on objects whose surfaces are to be coated with a coating made of nanomaterials .

The first step comprises the dry cleaning and activation with atmospheric plasma of the surfaces to be coated (block 10') .

The second step is a step of pre-heating the surfaces to be coated (block 20') .

The third step is a spraying step, or "spray coating", of the nanomaterial on the surfaces to be coated (block 30') . This step is followed by a step of pre-heating in the oven (block 40'), a step of heating in an oven with multiple stages controlled at different temperatures (block 50') and a final cooling step (block 60') .

During the pre-heating step, the gasses are evaporated and a thermal stability of the material is obtained before the entrance into the heating oven.

In the heating oven the various independent and thermo-controlled areas allow the attainment of the surface softening temperature which make the nanomaterial adhere to the support .

A plant indicated as a whole with reference numeral 100 and adapted to realize the steps of the process described above is visible in a side view in Figure 2 and in a top view in Figure 3.

In particular, the plant 100 comprises a plurality of subsequent work stations, among which:

- a dry cleaning and activating station 10 which uses atmospheric plasma to dry clean and activate the surfaces to be coated;

- a station for pre-heating 20 the surfaces to be coated;

- a spraying station 30 to coat the surfaces with a nanomaterial coating;

- a pre-heating oven 40, an oven 50 with multiple stages controlled at different temperatures and a cooling station 60.

Therefore, each work station of the plant 100 performs a specific function and allows guaranteeing the correct sedimentation of the nanomaterial on the support surface and the correct fixing thereof. The plant 100 is therefore of the modular type and each module has a system of sensors and actuators which are used to set certain and repeatable values during the production step.

The plant may be controlled in each single module thereof by means of a respective programmable logic controller (PLC) , possibly associated with a user interface, preferably equipped with a touchscreen, by means of which it is possible to set operating data.

A centralized system allows an operator to control the entire production cycle of the material. The centralized system allows the setting of saved recipes (programs) .

Again with reference to the plasma treatment, it should be noted that the plasma treatment and the plasma cleaning and activation create the best conditions for the subsequent sedimentation of a coating on surfaces made of plastic material, metal, aluminum or glass .

The dry cleaning and activation with atmospheric plasma allows the immediate execution of the subsequent material processing step. The use thereof guarantees a clean and profitable process. The high energy level of the plasma allows selectively breaking the structural bonds of the chemical or organic substances present on the surface of the material . With the micro-cleaning it is possible to completely remove unwanted starting materials even from delicate surfaces . Thereby, the best conditions are obtained for the subsequent sedimentation of the coating.

Plasma micro-cleaning also removes the smallest particles of dust which tenaciously sediment on the surface of the plastic materials due to the additives . The plasma induces a reaction which determines the complete detachment of the particles from the surface. Thereby, waste during the coating processes is significantly reduced. The chemical-physical reaction at the nanometric level allows obtaining high-quality surfaces with the highest degree of definition.

To better understand such effects, reference is now made to Figures 4 and 5.

Figure 4 shows a drop of water deposited on a surface treated according to the background art .

In such Figure, an angle of contact Q, i.e., a chemical-physical quantity defined by the angle formed by the intersection of a liquid- vapor interface with a liquid-solid interface or, less conventionally, a liquid-liquid interface, may be highlighted.

In the case shown, a liquid interface L (for example, water) with a solid interface are highlighted: an angle of contact Q is shown with a high value.

The smaller the angle of contact is, the more the surface is hydrophilic.

One of the properties of the T1O2 is the increase in the hydrophilicity of the surface if activated by means of light radiation.

Therefore, precisely by means of the light radiation, it may be observed whether the surface treated with the T1O2 nanomaterial actually increases the hydrophilicity thereof, by verifying the decrease of the angle of contact .

To better quantify such effects, the following Table 1 shows the results of tests carried out by applying, according to the modes of the present invention, a nanomaterial having the code AT16_SG02 to three different plastic substrates (Polystyrene - PS, Polymethylmethacrylate - PMMA and Polyester - PE) . TABLE 1

Key:

- PRO (PS substrate 1mm thickness)

*PRO without plasma pre-treatment

•PRO with plasma pre-treatment

- LAST (PMMA substrate 1.8mm thickness)

• LAST without plasma pre-treatment

• LAST with plasma pre-treatment

- EKO (PE substrate 0.7mm thickness)

•EKO without plasma pre-treatment

•EKO with plasma pre-treatment

In summary, it should be noted that the angle of contact of a sample of the same material (selected from three different plastic materials) , treated by using the plasma machine, is significantly improved with respect to the same sample untreated.

In particular, Figure 5 shows a drop of water deposited on a surface treated with nanomaterials in accordance with the invention, where an angle of contact q', much smaller than the angle of contact Q of

Figure 4, may be noticed.

Figure 6 shows an axonometric view of a dry cleaning and activating station 10 which uses atmospheric plasma. The products whose surfaces are to be treated are inserted into the station 10 by means of a conveyor belt 16, the speed of which may be adjustable.

This speed regulation allows a homogeneity of the plasma surface treatment based on the size and type of the material of the support to be treated.

The speed of the conveyor belt 16 may vary from 0.2 m/min to 1.5 m/min.

A particularly preferred speed is 0.2 m/min, which allows the surface to be treated to be covered well, avoiding untreated spaces.

The station also comprises a head 12 for the emission of plasma, whose height with respect to the piece to be treated is adjustable.

It has been observed that, for a better cleaning and activation capability, the chosen height between the plasma head and the substrate may preferably be equal to 2mm.

The station 10 also comprises a sensor which detects the start and the end of the inserted object so as to allow a reduction in consumption, in consideration of the fact that the plasma head 12 is activated only at the passage of a piece to be treated.

The station 10 also comprises a control panel 14 specific for this station 10, with speed, surface width and treatment settings according to the height of the plasma head, with the possibility of memorizing the desired specifications, and capable of also warning against problems and/or failures.

Figure 7 shows an axonometric view of a pre-heating station 20 according to an embodiment of the invention. Also in this case, the products whose surfaces are to be treated are fed to the station 20 by means of a conveyor belt 26.

The pre-heating preferably occurs by means of IR 24 infrared lamps.

The pre-heating station 20 offers the possibility of pre-heating the materials, which allows the remaining water to evaporate, giving the coating a greater possibility of support, and, for some materials, it allows maximizing the bonding capacity between the material and the coating.

The station 20 may also comprise a cooling fan 22 to favor the escape of the hot air present therein.

Figure 8 shows a view of a spraying station 30 to coat the surfaces with a nanomaterial coating according to an embodiment of the invention.

This is an automatic oscillating sprayer which includes a set of pumps associated with spraying guns which allow maximum homogeneity of sedimentation and an accurate weight .

In particular, the spraying station 30 may comprise 4 independent low-pressure automatic guns, wherein each gun may be adjusted in terms of capacity by means of appropriate adjustments .

The atomization and spraying pressure of the product is adjustable by means of appropriate valves .

It is also possible to adjust the oscillation speed of the guns, so as to guarantee the maximum homogeneity of treatment .

Furthermore, each individual gun may be tilted to operate on products which are not only planar, but also three-dimensional. Also in this case, a barrier of entering sensors allows the identification of the size of the product to be treated. This allows an optimization of the coating and avoids the waste of nanomaterial.

The pressure of the pump is adjustable.

The spraying station 30 reaches the optimal conditions for high quality finishings.

The features of it allow:

- optimizing consumption by evaluating and considering the actual size of the pieces to be treated;

- substantially reducing solvent and solid residue emissions in the atmosphere;

- a higher production speed, with respect to other equipment, capable of offering the same finished product quality level;

- an increase in the sprayed product/applied product ratio on the parts being processed.

The spraying station 30 is contained in a cabinet equipped with glass surfaces.

The gun guide system preferably consists of a carriage moved by a toothed belt driven by a brushless DC motor. The electronic speed and acceleration/deceleration control allows the optimal spraying on the products .

The purification plant consists of a series of dry filters contained in tanks positioned next to and below the spraying area.

The system allows reducing the amount of solid residues and solvents emitted into the atmosphere, within the limits established by current regulations . The conveyor belt is equipped with a vacuum system and is covered by a disposable paper or plastic film tape, which ensures the advantages of a continuous transport : cleaning of the underside of the substrate, uniformity of application between the edge and the plane of the substrate .

Downstream of the spraying station 30, a pre-heating oven 40 is provided, which constitutes the area in which the first evaporation of the compound is realized, to avoid introducing into the oven products which may be at risk of fire.

Such area is also used to bring the material to a first heating step, so as to increase the adhesion thereof to the support .

Downstream of the pre-heating oven 40 an oven 50 is provided, with different stages or areas (up to 8) in which each area may be individually controlled.

This control allows setting different temperatures for the individual areas and to manage heating and cooling curves which are suitable with respect to the support to be treated and appears to be a fundamental element, for example, for glass materials, since it allows the temperature of the piece to be lowered during the exit step and to avoid breakages on the piece itself.

The oven is static, so as not to alter the coating on the support .

The transport is preferably made with a fine metal mesh so as not to alter the temperatures of the processed pieces .

The speed of the conveyor belt may be set so as to establish the cooking time of the pieces . This allows the maximum plant management flexibility and the possibility of calibrating the temperatures and residence times inside the oven, so as to produce the best adhesion of the nanomaterial to the support . Finally, a cooling station 60 is provided, adapted to gradually lower the temperatures of the pieces, so as to facilitate the subsequent management by an operator. The pieces exiting the cooling station may be advantageously managed also by automatic systems, also by virtue of the presence of at least one sensor adapted to generate an end-of-stroke warning at the end of the treatment of the piece.

By applying the nanomaterial compound it is possible to give different properties to the surfaces of the materials .

The photocatalysts which may be activated in the visible region and, among these, preferentially, TiCt doped with Nitrogen (N) , allow the activation with visible and non-visible light, unlike the current T1O2- based products which are exclusively activated by means of UV radiation.

The nanomaterial also has a biocide component, including preferably Ag, which gives antibacterial properties .

The properties obtained are:

- NO _x (nitrogen oxides) reduction;

- VOCs (Volatile Organic Compounds) reduction;

- formaldehyde reduction;

- odor reduction;

- elimination of bacteria, germs and spores;

- CO (carbon monoxide) reduction.

The coating obtained shows the full functionality thereof in the presence of light .

The different color temperatures of white light will produce similar effects even if, the more the frequencies approach the blue light (6000K), the more the energy of the photon allows the overcoming of the "band gap". The addition of biocides, preferably Ag, allows an antibacterial effect even in the absence of light .

T1O2 produces a high hydrophilicity of the surface of the material, which allows obtaining self-cleaning products.

The great peculiarity of the material created is that of the activation by means of visible light . This allows using light sources without UV radiation and, therefore, such light source does not produce Ozone (O3) , which, instead, is what currently occurs when T1O2- based systems are used.

The plant 100 described allows creating lighting products with the features described above.

Figure 9 shows an axonometric view of a portion having the shape of a chain 200 of a lighting apparatus 200', said portion being treated, on the surfaces thereof, with the nanomaterial coating process.

In particular, a chain 200 of luminous elements 205 is visible, which, in a variant of the invention, involve the use of LED sources, in which each luminous element 205 is treated with a nanomaterial coating, according to the present invention, on the internal 210 and external surfaces 220 thereof.

Figure 10 shows an axonometric view of the entire lighting apparatus 200 of Figure 9.

Figure 10 shows the chain 200 which is associated with a rear cover 240, on which a supply box 260 and a card 230 for controlling the LEDs associated with the luminous elements 205 are placed.

In the lower part of the lighting apparatus 200' a screen 250 is provided, on which the nanomaterial coating according to the present invention is applied. Figure 11 shows an axonometric view of a modular component of the lighting apparatus 200' of Figure 10, i.e., a luminous element 205 is treated with a coating on the internal 210 and external surfaces 220 thereof .

Figure 12 shows an axonometric view of a further lighting apparatus 300 treated, on the surfaces thereof, in particular, on the surface of the emitting screen of the lighting apparatus, with the nanomaterial coating process.

In particular, the lighting apparatus 300 may be a standard lighting product, such as a LED panel, which has a screen coated with the nanomaterial according to the present invention and which, therefore, is capable of performing a purifying and sanitizing action on the air in contact with the surface itself.

Figure 13 shows an axonometric view of a projector 400 treated with a nanomaterial coating, in particular on the screen 410 of the projector 400 itself.

Figure 14 shows an axonometric view of an outdoor projector 500 treated with a nanomaterial coating, in particular on the screen 510 of the projector 500 itself.

In addition to the cleaning and sanitizing action on the air, in this case, the self-cleaning function of the product is highlighted, always considering the innovative aspect according to which the nanomaterial used may be activated by means of visible light .

Figure 15 shows an axonometric view of a ceiling light 600 treated with a nanomaterial coating on a surface 610 thereof.

The application of a nanomaterial coating on the screen of a watertight ceiling light allows giving the properties of the nanomaterial to the ceiling light, allowing realizing lighting plants for the sanitization, for example, of unhealthy environments . Finally, Figures 16 and 17 show axonometric views of bulbs 600, 700 treated with a nanomaterial coating on, respectively, the external surfaces 610 and 710 thereof, which may either be made of glass or plastic. The application of the nanomaterial on the surface of a common and pre-existing light source, both in glass and plastic, allows giving to the aforesaid common source the properties of the material .

Obviously, modifications or improvements may be made to the invention as described herein without departing from the scope of the invention as claimed below.