IT202200001316A1 - SUBLIMATIC PRINTING METHOD AND PRODUCT PRINTED WITH THIS METHOD - Google Patents

Description

SUBLIMATIC PRINTING METHOD AND PRODUCT PRINTED WITH

THIS METHOD

DESCRIPTION

TECHNICAL FIELD

The present invention refers to the sector of sublimation printing or sublimation thermoprinting, and in particular to sublimation printing on supports which can be compostable or possibly biodebradable.

STATE OF ART

In industry? note sublimation printing, also called sublimation printing or thermoprinting, used above all for the decoration of polymeric materials and synthetic fabrics, typically in polyester fibre. This printing methodology? widely appreciated because? guarantees high quality? of the finished product, allowing even very complex graphic subjects, such as photographic images, to be reproduced in a very accurate and defined way.

The procedure involves a first phase in which the desired graphic subject is printed, with a special water-based sublimation ink, on a temporary paper support called transfer. Printing consists of deposition of the graphic subject onto transfer paper, inverted mirror-like with respect to the appearance it must take on the finished product. This phase is completed with traditional tools, such as a common printing plotter.

In a second phase, the printed transfer paper sheet is coupled to the final support, so that the inks rest on the surface where you want the graphic subject to be reproduced. Pressure and heat are then applied to the transfer sheet and final support for between 30 and 180 seconds. The pressure makes the two surfaces adhere uniformly, while the heat transfers the graphic subject from the transfer paper to the definitive support. More? in detail, the applied temperature, which can? varying from 180?C to 220?C, causes the inks to sublimate which from the solid phase in which they are present on the transfer paper, pass to the gaseous phase and then expand and penetrate the surface layers of the definitive support where they return to the solid phase. In this way the graphic subject is transferred with great precision, forming a permanent and indelible image on the definitive support.

This system? particularly appreciated in the sportswear sector, promotional products, furniture, promotional objects and for large format prints, for example intended for communication campaigns such as flags, banners, and the like.

Although? Widely used and appreciated, sublimation printing is not free from disadvantages. As reported above, the final supports currently used must be polymeric materials, such as synthetic fabrics. Often such materials are not recyclable and certainly are not n? compostable n? biodegradable. They therefore require adequate disposal which involves costs and critical issues. Of course this problem? rather limited when considering a single object to be disposed of, but it is considerably amplified when, for example, an entire communication campaign reaches its end and therefore the entirety of it must be disposed of. of printed materials. In this regard, think for example of an important sporting event, for example a cycling race, for which numerous large format printed materials are produced, such as promotional banners intended to be visible for several hundred meters of the route. At the end of the sporting event, what can? last even just a few hours, often these banners have exhausted their function and must be disposed of.

? therefore felt the need for an improved sublimation printing method that allows the use of definitive supports that cannot be used with known sublimation printing methods, which are recyclable and/or which have a reduced or zero environmental impact.

AIMS AND SUMMARY OF THE FINDING

? purpose of the present invention is to overcome the drawbacks of the known art.

In particular, an aim of the present invention is? that of making available a sublimation printing method that can use definitive supports that cannot be used with known sublimation printing methods. For example, it can use definitive supports that are recyclable or have minimal or no environmental impact, even in the case of incorrect disposal.

Furthermore, an aim of the present invention is? that of making available a sublimation printing method that guarantees performances and results similar to or better than the methods of the prior art.

Again, a task of the present invention? that of making available a sublimation printing method which is simple to implement and which does not entail significant increases in costs compared to the methods of the prior art.

Finally, a task of the present invention? that of making available a sublimation printed product with minimal or no environmental impact.

These and other objects and tasks of the present invention are achieved by means of a sublimation printing method and by means of a printed product in accordance with the attached claims, which form an integral part of the present description.

In accordance with a first aspect, the invention concerns a sublimation printing method comprising the phases of:

- prepare a graphic subject;

- prepare a sheet of transfer paper;

- prepare a silicone sheet comprising at least one silicone-based surface layer;

- prepare a substrate;

- print the graphic subject on the transfer paper sheet in the default orientation with sublimation inks;

- couple the transfer paper sheet to the silicone sheet, so that the graphic subject rests on the silicone-based layer;

- apply pressure and temperature suitable to transfer the graphic subject from the transfer paper sheet to the silicone sheet;

- couple the silicone sheet to the substrate, so that the graphic subject rests on the substrate; And

- apply pressure and temperature suitable to transfer the graphic subject from the silicone sheet to the substrate.

Thanks to the particular sequence of phases, the method of the invention allows the use of substrates that cannot be used in known sublimation printing processes.

Preferably the step of applying pressure and temperature suitable for transferring the graphic subject from the transfer paper sheet to the silicone sheet includes the step of applying a temperature of approximately 200?20?C.

This phase guarantees the optimal transfer of the graphic subject and can be carried out with the equipment traditionally used in known sublimation printing processes.

Preferably the step of applying pressure and temperature suitable for transferring the graphic subject from the silicone sheet to the substrate includes the step of applying a temperature of approximately 150?10?C.

This temperature allows the use of substrates which, at the temperatures commonly used in sublimation printing processes of a known type, soften or melt. For example, it allows the use of polypropylene, Mater-Bi or PLA substrates.

In accordance with some embodiments of the invention, the graphic subject has its own predefined correct orientation. In this case the method preferably includes the steps of:

- prepare a graphic subject with a predefined correct orientation;

- print the graphic subject on the sheet of transfer paper in the correct orientation;

- transfer the graphic subject from the transfer paper sheet to the silicone sheet, in the mirror orientation of the correct one; And

- transfer the graphic subject from the silicone sheet to the substrate, in the correct orientation.

These steps allow the graphic to appear on the printed product in its predefined correct orientation.

In some embodiments, the substrate is made of polypropylene (PP).

These embodiments allow the environmental impact to be limited because polypropylene? recyclable.

In some embodiments, the substrate is compostable.

In some embodiments, the substrate is biodegradable.

These embodiments allow the use of substrates having minimal or no environmental impact.

In some embodiments the compostable substrate includes a surface layer suitable for receiving the print.

This option allows you to prepare substrates made from the union of different layers, in such a way as to be able to optimize their characteristics and costs.

Advantageously, is the surface layer suitable for receiving the print? made of a compostable polymer, possibly biodegradable. Preferably this polymer? for example Mater-Bi or PLA.

In accordance with a second aspect, the invention concerns a printed product comprising a surface layer suitable for receiving the print, and in which the surface layer suitable for receiving the print:

- includes a graphic subject made up of sublimation inks transferred via sublimation; And

- ? made of polypropylene or a compostable polymer, possibly biodegradable.

This printed product cannot? be obtained through known sublimation printing processes, and therefore allows a greater degree of freedom? for the user.

In some embodiments of the invention, the entire printed product is compostable. In some embodiments of the invention, the entire printed product is biodegradable.

This allows us to minimize or cancel the environmental impact of the printed product, even if the latter is lost or disposed of incorrectly.

Further characteristics and objects of the present invention will appear more clearly from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will come described below with reference to some examples, provided for explanatory and non-limiting purposes, and illustrated in the attached drawings. These drawings illustrate different aspects and embodiments of the present invention and, where appropriate, reference numerals illustrating similar structures, components, materials and/or elements in different figures are indicated by similar reference numerals.

Figure 1 schematically shows a phase of the method of the invention;

Figure 2 schematically shows another phase of the method of the invention; And

Figure 3 schematically shows a further phase of the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

While the invention is susceptible to various modifications and alternative constructions, some preferred embodiments are shown in the drawings and will be described below in detail. It must be understood, however, that there is no There is no intention to limit the invention to the specific embodiment illustrated, but, instead, the invention is intended to cover all modifications, alternative constructions, and equivalents that fall within the scope of the invention as defined in the claims.

The use of ?for example?, ?etc?, ?or? means non-exclusive alternatives without limitation unless otherwise indicated. The use of ?include? means ?includes, but not limited to? unless otherwise indicated.

In the context of this discussion, the terms ?compostable?, ?compostability? and similar are intended in accordance with the UNI-EN 13432:2002 standard. Regarding the terms ?biodegradable?, ?biodegradability?? and similar, there is currently no standard recognized unambiguously by national or supranational bodies, with the sole exception of the UNI EN ISO 14851:2019 standard relating to polymers and plastic materials. Therefore, the concept of biodegradability? ? understood below in an intuitive way and represents a more significant requirement? more stringent than that of compostability. In other words, in the context of this discussion it is considered that a compostable product or material can also be biodegradable, depending on the definition adopted. Conversely, in the context of this discussion, a biodegradable product or material is? certainly compostable.

An improved sublimation printing method in accordance with the invention is described below. The method includes the steps of:

- prepare a graphic subject 10;

- prepare a sheet of transfer paper 12;

- prepare a silicone sheet 14 comprising at least one silicone-based surface layer;

- prepare a substrate 16;

- print the graphic subject 10 on the transfer paper sheet 12 with sublimation inks, in such a way as to obtain a first intermediate product 18;

- couple the transfer paper sheet 12 to the silicone sheet 14, so that the graphic subject 10 rests on the silicone-based layer;

- apply pressure and temperature suitable to transfer the graphic subject 10 from the transfer paper sheet 12 to the silicone sheet 14, so as to obtain a second intermediate product 20;

- couple the silicone sheet 14 to the substrate 16, so that the graphic subject 10 rests on the substrate 16; And

- apply pressure and temperature suitable to transfer the graphic subject 10 from the silicone sheet 14 to the substrate 16, in such a way as to obtain the printed product 22.

How can the expert person? understand well, some of the phases and some of the devices and materials used in the method of the invention are similar or the same as similar phases and similar devices and materials used in the sublimation printing methods of the prior art.

The sublimation inks used in the method of the invention can be the same ones commonly used in known sublimation printing methods. These inks are water-based and, following specific laboratory tests commissioned by the applicant, were found to be compostable.

For example, sublimation inks suitable for use in the method of the invention are those produced by

China and marketed under the name DIGISTAR HI-PRO by

The transfer paper 12 used in the method of the invention can be the same commonly used in known sublimation printing methods. This transfer paper is 12, so in itself? known, ? configured to receive the print of the graphic subject 10, obtained with sublimation inks using a conventional printing device, such as for example a plotter 24. The transfer paper 12 is furthermore configured to firmly hold the sublimation inks during the handling and possible storage of the first intermediate product 18. Finally, the transfer paper 12 is configured to release the sublimation inks under the action of heat, in such a way as to allow the transfer of the sublimation inks, and therefore of the graphic subject 10.

A transfer paper 12 suitable for use in the method of the invention can for example have one or more? of the following characteristics, where the reference standards are shown in brackets:

- Weight: 65 ?3 g/m<2 >(ISO 536);

- Thickness: 100 ?5 ?m (ISO 534);

- Brightness? R457: 86?2% (ISO 2470);

- Cobb 60 water absorption: 30 -5 g/m<2 >(ISO 535);

- Air permeance (porosity): 835 -101 Ml/min (ISO 5636-3).

For example, a transfer paper 12 suitable for use in the method of the invention? the paper marketed under the name THIN65 by

Furthermore, the phase of printing the graphic subject 10 on the sheet of transfer paper 12 can be carried out using a printing device of a known type, for example via a 24 plotter or inkjet printer. Such printing devices are commonly used in sublimation printing processes of a known type to print the graphic subject 10 on the transfer paper sheet 12 with sublimation inks, so as to obtain an intermediate product.

How can the expert person? well understand, in the method of the invention two successive intermediate products 18, 20 and two sublimation transfer phases are used. In particular, the method includes:

- A first transfer phase by sublimation which involves applying pressure and temperature to transfer the graphic subject 10 from the first intermediate product 18 (transfer paper sheet 12) to the silicone sheet 14, so as to obtain a second intermediate product 20. - A second transfer phase by sublimation which involves applying pressure and temperature to transfer the graphic subject 10 from the second intermediate product 20 (siliconised sheet 14) to the substrate 16, so as to obtain the printed product 22.

These sublimation transfer steps can be performed with conventional equipment, commonly used in known sublimation printing processes. For example, these phases can be carried out using hot plate presses 26 or using calender or heated roller presses. The hot plate presses 26 are suitable for obtaining intermediate products 18, 20 or molded products 22 having a flat development that can be included within the area of the press plates. The heated roller calender? suitable for obtaining intermediate products 18, 20 or molded products 22 having a continuous flat development of a priori indefinite length.

The pressure values and application times used in the two sublimation transfer phases are those commonly used in known sublimation printing processes. As regards the temperature values, however, a more detailed treatment? detailed? reported further.

In some embodiments, the graphic subject 10 has its own predefined correct orientation. For example, if the graphic subject 10 includes writing and/or a photographic image of a truly existing subject, the correct orientation is? uniquely defined in relation to the right-left direction. Since? the orientation of the graphic subject 10 is reversed mirrorwise at each contact transfer step, the method of the invention can? advantageously foresee the following phases:

- prepare a graphic subject 10 having a predefined correct orientation;

- print the graphic subject 10 on the transfer paper sheet 12 in the correct orientation;

- transfer the graphic subject 10 from the transfer paper sheet 12 to the silicone sheet 14, in the mirror orientation of the correct one; And

- transfer the graphic subject 10 from the silicone sheet 14 to the substrate 16, in the correct orientation.

The method of the invention, unlike known methods, also involves the use of a silicone sheet 14. This silicone sheet 14 can for example comprising a support layer, for example made of paper or polyethylene terephthalate (PET), on which? applied a layer of silicone coating. For example, in the method of the invention, the siliconized sheet 14 can be made of silicone paper, in itself? Note. Is the paper intended to receive the silicone layer? preferably coated paper, that is? treated to increase its smoothness. This treatment, in itself? widely known, involves the deposition of an additional patina, hence the term coated paper, obtained with one or more? materials selected from: kaolinite, calcium carbonate, bentonite or talc. Siliconized paper and siliconed PET are commonly used in industry, for example as an anti-adhesive support for the handling, transport and storage of labels, graphic decorations and self-adhesive tapes, or for other industrial products characterized by their own adhesiveness. or stickiness? superficial.

A silicone sheet 14 suitable for use in the method of the invention can for example be obtained from a silicone paper having one or more of the following characteristics, where the reference standards are shown in brackets:

- Weight: 100?6 g/m<2 >(ISO 536);

- Thickness: 96?8 ?m (ISO 534);

- Breaking load: ?75 N/15mm (MD DIN EN 1924-2);

?50 N/15mm (CD DIN EN 1924-2);

- Top side smoothness ?300 s (DIN 53107-A);

bottom side ?20 s (DIN 53107-A);

- Detachment: 30?15 cN/25mm TESA TAPE A 7475 (FINAT 10);

- Moisture content: 4.2?1% (DIN EN 20287).

A silicone paper suitable for use in the method of the invention? for example the paper marketed with the code MPT100M100 by

In accordance with some embodiments of the invention, the method of the invention includes the step of preparing a substrate 16 comprising at least one layer of polypropylene (PP) or a compostable polymer, such as for example Mater-Bi or polylactic acid (PLA ). Is the layer made of polypropylene or compostable polymer? suitable for receiving print.

In accordance with some embodiments of the invention, the method of the invention includes the step of preparing a compostable substrate 16.

In accordance with some embodiments of the invention, the method of the invention includes the step of providing a biodegradable substrate 16.

In accordance with some embodiments of the invention, the compostable, possibly biodegradable, substrate 16 includes a structural layer 28 and a surface layer 30 suitable for receiving the print.

In accordance with some embodiments, the structural layer 28 can be flexible, for example made of organic or natural fibres. The structural layer 28 can be obtained for example with a fabric, a non-woven fabric or a mat of organic or natural fibres.

The structural layer 28 can be achieved using one or more? of the following fibres: bamboo, hemp, linen, silk, cotton, cellulose, viscose, raffia, jute or kenaf. Other fibers suitable for making the structural layer 28 in whole or in part are those obtained from fruit processing waste (such as apples, oranges or bananas), or even those marketed by with the trade name TENCEL<? >and which can be obtained from eucalyptus (in this case also called Lyocell<?>) or from beech (also called Modal<?>).

In accordance with some embodiments, the structural layer 28 can be rigid or semi-rigid, for example made of cardboard, cork or wood. For example, the structural layer 28 can include a panel made of natural wood, laminated wood or plywood, or pressed wood fibers, chips or flakes.

The surface layer 30 suitable for receiving the print can be made with a compostable, possibly biodegradable polymer. For example, the surface layer 30 can? be made with a material based on polybutylene adipate terephthalate (PBAT) and starch. A polymer suitable for this use? for example produced and marketed under the name Mater-Bi by

The structural layer 28 allows the compostable substrate 16 as a whole to obtain adequate mechanical characteristics of stiffness and resistance, while at the same time limiting the quantity of compostable polymer required. In this way the overall costs of the compostable substrate 16 are limited.

In accordance with other embodiments, the compostable substrate 16 is ? monolithic, made solely of a compostable polymer, possibly biodegradable, suitable for receiving printing. Preferably, this polymer is of the type described above, for example Mater-Bi or PLA.

As highlighted above, the experimental tests conducted by the applicant have highlighted the need? to use two subsequent intermediate products 18, 20, the first (indicated with 18) obtained with the printing of the graphic subject 10 on the transfer paper 12 and the second (indicated with 20) obtained with the transfer by sublimation of the graphic subject 10 from the first product intermediate 18 on the silicone sheet 14.

This apparent complication arises from the impossibility? to use only one intermediate product obtained with direct printing, n? on transfer paper 12 n? on the silicone sheet 14.

In fact, direct printing on the silicone sheet 14 is not possible due to the fact that the intrinsic characteristics of this support do not allow the sublimation inks to dry correctly. Consequently, by proceeding with direct printing on the silicone sheet 14, an extremely delicate intermediate product would be obtained on which the graphic subject 10 risks being ruined by any accidental contact. Would this event degrade the quality? of the printed product 22 in an unacceptable manner.

Furthermore, ? it emerged that the conventional intermediate product, obtained by printing on transfer paper 12, cannot? be used to transfer the graphic subject 10 directly onto a substrate 16 of polypropylene or a compostable polymer of the type described above by sublimation. In fact, the known type of sublimation transfer process involves the application of a temperature of approximately 200°C. At this temperature the polypropylene and the compostable polymers considered here soften or melt, and determine the definitive adhesion of the intermediate product to the substrate 16, making it impossible to obtain the desired printed product 22.

For these reasons, in the method of the invention, two successive intermediate products 18, 20 and the two sublimation transfer phases described above are used.

Preferably, the first sublimation transfer phase involves the application of a temperature of approximately 200?20?C. Preferably this application occurs for a time between 30 and 180 seconds. These parameters are those commonly adopted in known sublimation printing processes.

Preferably, the second sublimation transfer phase involves the application of a temperature of approximately 150?10?C. Preferably this application occurs for a time between 30 and 180 seconds. The temperature is around 150?10?C, significantly higher? lower than that commonly applied, does not cause the melting of the polypropylene or the compostable polymer, and allows the correct transfer of the graphic subject 10 and therefore the obtaining of the printed product 22.

In accordance with a second aspect, the invention also concerns the molded product 22 obtained with the method described above. In particular, the invention concerns a printed product 22 comprising a surface layer 30 suitable for receiving the print and in which the surface layer 30 suitable for receiving the print:

- includes a graphic subject 10 made up of sublimation inks transferred via sublimation; And

- ? made of polypropylene or a compostable polymer, possibly biodegradable.

Advantageously, the molded product 22 of the invention is entirely compostable, possibly biodegradable. These and other technical characteristics of the molded product 22 of the invention can be unambiguously deduced from the description of the method described above.

In particular, in some embodiments, the molded product 22 comprises a substrate 16 comprising at least one layer of polypropylene (PP).

In other embodiments, the printed product 22 comprises a compostable, possibly biodegradable, substrate 16.

Advantageously, the compostable substrate 16 can comprising a structural layer 28 and a surface layer 30 suitable for receiving the print.

The structural layer 28 can be flexible, for example made of organic or natural fibers such as cotton, linen, hemp, viscose, bamboo, cellulose or similar. The structural layer 28 can be obtained for example with a fabric, a non-woven fabric or a mat of organic or natural fibres.

Alternatively, the structural layer 28 can be rigid or semi-rigid, for example made of cardboard or wood. In particular, the structural layer 28 can include a panel made of natural wood, laminated wood or plywood or pressed wood fibers, chips or flakes.

The surface layer 30 suitable for receiving the print can be made with a compostable, possibly biodegradable polymer. For example, the surface layer 30 can? be made with a material based on polybutylene adipate terephthalate (PBAT) and starch. A polymer suitable for this use? for example produced and marketed under the name Mater-Bi by

Again by way of example, the surface layer 30 can? be made with polylactic acid (PLA).

In accordance with other embodiments, the compostable substrate 16 can be monolithic, made solely of a compostable polymer, suitable for receiving printing. Preferably, this polymer is of the type described above, for example Mater-Bi or PLA.

How can the expert person? well understood, the present invention overcomes the drawbacks of the known art.

In particular, the present invention makes available a sublimation printing method that can use definitive supports that cannot be used with known sublimation printing methods. For example, can use definitive supports with minimal or no environmental impact, even in the case of incorrect disposal.

Furthermore, the present invention makes available a sublimation printing method which guarantees performances and results similar or better than the methods of the prior art.

Furthermore, the present invention makes available a sublimation printing method that is simple to implement and which does not entail significant increases in costs compared to the methods of the prior art.

Finally, the present invention makes available a sublimation printed product 22 with minimal or no environmental impact.

The invention like this? conceived? susceptible to numerous modifications and variations, all falling within the scope as resulting from the attached claims.

The technical characteristics described by way of example with reference to a specific embodiment can be adopted in other embodiments.

Finally, all details can be replaced by other technically equivalent elements. In conclusion, the materials used, as well as? the contingent shapes and dimensions may be any according to the specific implementation needs without thereby departing from the scope of protection of the following claims.

Claims (9)

1. Sublimation printing method including the steps of: - prepare a graphic subject (10); - prepare a sheet of transfer paper (12); - prepare a silicone sheet (14) including at least one silicone-based surface layer; - prepare a substrate (16); - print the graphic subject (10) on the transfer paper sheet (12) with sublimation inks, so as to obtain a first intermediate product (18); - couple the transfer paper sheet (12) to the silicone sheet (14), so that the graphic subject (10) rests on the silicone-based layer; - apply pressure and temperature suitable to transfer the graphic subject (10) from the transfer paper sheet (12) to the silicone sheet (14), so as to obtain a second intermediate product (20); - couple the silicone sheet (14) to the substrate (16), so that the graphic subject (10) rests on the substrate (16); And - apply pressure and temperature suitable to transfer the graphic subject (10) from the silicone sheet (14) to the substrate (16), in such a way as to obtain the printed product (22). 2. Method according to claim 1, wherein the step of applying pressure and temperature suitable for transferring the graphic subject (10) from the transfer paper sheet (12) to the silicone sheet (14) includes the step of applying a temperature of around 200?20?C. 3. Method according to claim 1 or 2, wherein the step of applying pressure and temperature suitable for transferring the graphic subject (10) from the silicone sheet (14) to the substrate (16) includes the step of applying a temperature of approximately 150?10?C. 4. Method in accordance with one or more? of the previous claims, in which the graphic subject (10) has its own predefined correct orientation, and further comprising the phases of: - prepare a graphic subject (10) having a predefined correct orientation; - print the graphic subject (10) on the sheet of transfer paper (12) in the correct orientation; - transfer the graphic subject (10) from the transfer paper sheet (12) to the silicone sheet (14), in the mirror orientation of the correct one; And - transfer the graphic subject (10) from the silicone sheet (14) to the substrate (16), in the correct orientation. 5. Method in accordance with one or more? of the previous claims, further comprising the step of preparing a substrate (16) in polypropylene (PP). 6. Method in accordance with one or more? of claims 1 to 4, further comprising the step of preparing a compostable, possibly biodegradable, substrate (16) having a surface layer (30) suitable for receiving the print. 7. Method according to the previous claim, wherein the surface layer (30) suitable for receiving the print? made of a compostable polymer, possibly biodegradable. 8. Printed product (22) comprising a surface layer (30) adapted to receive printing and wherein the surface layer (30) adapted to receive printing: - includes a graphic subject (10) made up of sublimation inks transferred via sublimation; And - ? made of polypropylene or a compostable polymer, possibly biodegradable. 9. Printed product (22) according to claim 8, wherein the entire product is? compostable, possibly biodegradable.