IT201800005172A1 - A cardboard container preferably of the corrugated type and with digital UV ink printing - Google Patents

Description

Description accompanying the patent application for industrial invention entitled:

A CARDBOARD CONTAINER PREFERABLY OF THE TYPE

CORRUGATED AND WITH DIGITAL PRINTING WITH UV INK

Scope of the invention

The present invention relates to the technical sector relating to cardboard packaging, preferably of the corrugated type.

In this case, the invention refers to a particular type of cardboard, preferably corrugated, for the production of packaging, such as boxes for food, on which the print made is a digital print on a metallized support suitable for contact with food, in so that the printing is of high quality and achievable with a very flexible and economical processing cycle.

Brief notes on the known art

Cardboard packaging has been known for a very long time. Among these we can, for example, include boxes for fruit and vegetables, therefore fruit and / or vegetables in general.

A particular type of cardboard used to shape a packaging, for example a box or a container in general, is that of the corrugated type.

Corrugated cardboard can be of various types. In one case there is single-wave corrugated cardboard in which a layer (or sheet) of cardboard is corrugated and then glued between two flat cardboard layers (or sheets) that represent the two upper and lower covers.

For example, figure 1 of the prior art shows the two upper (120S) and lower (110S) flat layers which comprise the corrugated layer (115S) between them.

In another case, the corrugated cardboard can be that in double wave which provides a lower layer 110D on which an internal corrugated layer 115D is applied. A flat intermediate layer 120D is applied to the internal corrugated layer 115D and, over the intermediate layer 120D, a further corrugated layer 125D is applied on top with a flat upper layer 130D.

In this case, therefore, there are two corrugated layers (115D, 125D) both interposed between an upper flat layer and a lower flat layer.

The characteristic of corrugated cardboard, regardless of the number of layers with which it is made (single or double wave), is to have a good compromise between the weight of the packaging and mechanical strength, combined with a low environmental impact thanks to recyclability.

Once produced, it can be destined for various uses including the production of packaging, such as boxes for the transport of foodstuffs or boxes of the American type (just to name a few).

Often times, for example when the cardboard is intended for packaging, it is necessary to make prints (therefore images, shapes, letters of any kind) on a surface of the packaging. For example, fruit crates often have graphic representations on their external surface that indicate the type of product transported (for example strawberries to indicate that the crate will be used for the transport of strawberries or fruit in general).

In the current state of the art, however, the graphic images that are shown on the cardboard are made with flexographic or offset printing, but the result obtained is not always the best as, in the case of using flexographic printing, a graphic result will not be obtained. optimal while, in the case of the use of offset printing, the number of processes necessary to create a finished product makes packaging for fruit and vegetables anti-economic.

Furthermore, with current techniques, it is necessary to use printing plates and this obviously lowers the flexibility of the system itself and increases the risk of waste.

Summary of the invention

It is therefore an object of the present invention to at least partially solve the aforementioned technical drawbacks.

In particular, it is an object of the present invention to provide a new type of cardboard, preferably of the corrugated type, which allows to obtain a print on the cardboard, and therefore on any packaging obtained as a finished cardboard processing product, which is of better quality and lasting. in time.

It is also the purpose of the present invention to provide a new type of cardboard, and related packaging or container obtained therefrom, provided with printing that is also economical in its production, as well as allowing flexible production and with a low number of rejects.

It is also the purpose of the present invention to provide the related method for obtaining a cardboard suitable for the creation of a packaging that has a high quality print, lasting over time and in which the production process is also economical.

These and other purposes are therefore achieved with the present cardboard, preferably corrugated (1), for making a package, according to claim 1.

Said cardboard comprises, at least in part thereof, a metallized coating and a UV ink printing arranged on said metallized coating.

In accordance with this solution, all the aforementioned technical drawbacks are easily solved.

In particular, printing with UV inks is of excellent quality and lasting over time. In this case, therefore, the print quality is superior to known art prints.

Thanks to this solution, it is therefore possible to create packaging, obtained by means of special die-cutting of the cardboard, which show high quality and long-lasting designs.

The UV inks used in the digital printing process are suitable for contact with food.

The use of the metallic coating as a substrate for printing has the additional technical effect of shielding the cardboard sheet well when applied, thus ensuring that the moisture in those areas does not penetrate. In this way, the packaging created is a packaging that is more resistant to moisture than traditional packaging.

Advantageously, the printing is digital. In this way the process is fast and well automated without requiring clichés and reducing the number of rejects. In this sense, therefore, the economic aspect is also of considerable importance; in fact, thanks to the particular production process capable of reducing processing phases and times, as illustrated below, the prerogative of economy typical of cardboard is maintained.

Advantageously, the cardboard is of the corrugated type. In this way it is easy to make a cardboard in which its upper cover, normally obtained in a corrugated cardboard production process, is now replaced with a metallized cover on which this digital UV ink printing is then specially made.

The metallic coating makes it difficult to anchor the inks and, for this reason, it was advantageously necessary to use a type of specific primer distributed on the metal coating.

Also described here is a method for obtaining a cardboard intended for the formation of a packaging, the method providing for the phase of:

- Creation of a cardboard sheet;

- Printing on at least one surface (3) of said cardboard sheet;

- In accordance with the invention, the surface intended to be printed is provided with a metallized coating and the printing phase takes place through the distribution on said metallized surface of a UV ink.

Advantageously, the printing is digital and takes place within a special printing section (D1, D2, D3).

Further advantages can be deduced from the dependent claims.

Brief description of the drawings Further characteristics and advantages of the present corrugated cardboard for the production of packaging in general, and the relative manufacturing method, according to the invention, will become clearer with the following description of some embodiments, given by way of non-limiting example , with reference to the attached drawings, in which:

- Figure 1 shows a corrugated cardboard structure with double and single wave in accordance with the known art; - Figure 2 shows an example of single-wave corrugated cardboard and highlights the structure with which the metallized upper cover 3 is formed;

- Figure 2A details in a more precise way the layers that make up the upper sheet 3 of the corrugated cardboard (ie the metallized cover);

- Figure 3 is a schematic of a known art production line for obtaining a corrugated cardboard;

- Figure 4 shows the three in-line sections (D1, D2, D3) that make up the digital printing line, and in particular the section or unit D1 for the distribution of the "Primer", D2 the section or printing unit in which the UV ink is used and the last section or unit D3 in which the UV lamps are set up for the final drying of the distributed ink;

- Figure 5A schematises the heads 50 which spray the UV ink inside the digital printing section D2, according to a predetermined drawing stored electronically, while Figure 5B schematises the drying phase of the print with ultra violet lamps at the inside section D3.

Description of some preferred embodiments In accordance with the invention, as per the attached figures, the production step of a corrugated cardboard on which a print of any kind is reported is described.

The printing, as detailed below, is made with UV ink on a metal base support and with digital printing technique within a special printing section (D1, D2, D3).

The corrugated cardboard thus obtained can then be normally punched to form a packaging, for example boxes for food, such as fruit and vegetable products.

Obviously, the present invention does not exclude the possibility of being able to produce containers of different shapes and intended for different uses, for example American containers.

As mentioned, the preferred configuration of the invention is aimed at the processing of corrugated cardboard, therefore with single, double wave or with any number of waves.

Corrugated cardboard, in fact, is widely used in the production of packaging and, moreover, its traditional production process goes well with the improvement modification in accordance with the present invention.

However, as will be apparent even more clearly from the rest of the present description, nothing would exclude the possibility of adapting the present inventive concept to any type of cardboard, not necessarily of the corrugated type.

That said, a description follows, in a non-limiting way, of the production phase of a container, for example a fruit box, in accordance with the invention and through the creation of a corrugated cardboard.

Three processing phases can be distinguished:

- Phase 1): Production of the corrugated cardboard sheet; - Phase 2): Printing of the metallic outer cover; - Phase 3): Die-cutting of the sheet, in order to then be able to conform it according to the final shape, for example the box for fruit and vegetables or food in general.

Figure 2 shows, for simplicity, a single-wave corrugated cardboard in which a single corrugated layer 4 is included between the two flat sheets outside 3 and inside 2 and which therefore represent the two visible surfaces of the cardboard.

In accordance with the invention, at least one of said two sheets (2, 3) includes an external metallized coating, in such a way as to create the support on which to apply the UV digital printing.

In particular, according to the invention, the outer cover 3 is preferably metallized, which is precisely defined as a metallized outer cover.

As shown schematically in the enlargement A of Figure 2A, this outer cover 3 is preferably made up of at least three superimposed layers (10, 20, 30) and of which:

- The outermost layer 10 is in PET Silver (Polyethylene terephthalate) and therefore represents the metallized layer. The metal it covers can be silver or gold in color.

- The intermediate layer 20 is in LDPE (English acronym indicating low-density polyethylene) which LDPE is a thermoplastic polymer obtained from petroleum. Said intermediate layer 20 is therefore an adhesive necessary to hold together the outer layer 10 in PET silver with an inner layer 30.

- The inner layer 30 is made of paper, preferably of the 100% recycled type, in such a way as to be able to adhere in a traditional way, as explained below, to the corrugated layer 4 during its production process of the corrugated cardboard.

This metallized outer cover 3 is generally produced upstream of the production process and supplied as a tape ready for making corrugated cardboard, replacing the normal cardboard tape commonly used.

Once this metallized cover 3 has been produced or in any case supplied, one proceeds to the step of making the corrugated cardboard which in itself uses a known system but replaces the traditional cardboard tape 3 with the externally metallized tape.

In particular, this procedure provides for the coupling through glue of the corrugated layer 4 with the lower cardboard sheet 2 and the metallized cover 3 (which now, as mentioned, replaces, according to the invention, the classic cardboard sheet) .

The manufacturing technique of a corrugated cardboard is per se well known in the state of the art and for this reason it is only briefly described here for the purpose of greater clarity and with reference to Figure 3.

Figure 3 therefore schematises a plant for making corrugated cardboard.

The coils are rotated by the motors 1A, 1B and 1C according to the destination layer; the wave papers are corrugated in special cylinders and coupled to the inner cover. In the case of a single wave, the wave is coupled to the inner cover while in the case of a double wave the additional wave is coupled to the central tense.

The sub-phase described takes place between the gluing cylinder and the pressure cylinder in very short times (about 0.01 seconds for 200 m / min of sheet produced) and generates one layer in the case of a single wave or two layers in the case of a double wave. , to be glued to the outer metallic print cover.

Figure 3 therefore shows with the numbering 1A a first motorized reel on which it is wound in cardboard tape which will form the lower cover 2 (also called inner cover).

The numbering 1B indicates the motorized reel from which the cardboard tape unwinds for the formation of the corrugated intermediate layer, while the numbering 1C indicates the motorized reel from which the previously produced and supplied metallized cover 3 unwinds.

The group of rollers 6A represents a set of gluing rollers while the roller 4a is a corrugating roll. In this way the cardboard tape coming from the reel 1B is corrugated through a suitable corrugating roller 4a and is then glued in the group 6A with the cardboard tape coming from the reel 1A.

At this point, to complete the corrugated cardboard, it is necessary to couple the ribbon formed by the corrugated cardboard glued to the lower ribbon with the metallized cover coming from the reel 1C.

The coupling and gluing of the layers of the sheet in single or double wave (wave (s), inner cover, central stretch and metallized print cover) takes place in the hot surfaces 8a, where the bursting of the glue and the release of the humidity thanks to the action of the felts (8a, 9a, 10a, 11a).

The coupled layers form a flat planar sheet which is cut according to the required length and width measurements in the rotary cutter 13a and in the crease cutter 12a and finally stacked in the collector 14a.

As can be seen from the description, the cardboard production process does not require any changes compared to the traditional method since the outer metallized cover is made in several layers (10, 20, 30) and of which the outer layer 10 is metallized, which is intended for printing, and the innermost layer 30 in paper, in such a way as to be perfectly glued to the corrugated layer as in the traditional process.

This brings a considerable advantage, since this technique for producing the metal layer does not require particular modifications to the production process of the corrugated cardboard.

At this point the corrugated cardboard produced is ready to enter the printing line.

We then move on to the printing phase in which the cardboard is printed in correspondence with its metallized outer surface, therefore on the part of the metallized outer cover.

To do this, as schematically shown in figure 4, the cardboard enters a printing station (D1, D2, D3) which, according to the invention, is a digital UV printing.

The cardboard can, for example, be conveyed into this station through a suitable conveyor belt such that, at the exit from the cardboard preparation station, it is immediately fed towards the printing station.

The printing station consists of three successive sections.

With reference to Figure 4, there is therefore a first section D1 where a "primer" is distributed;

The term "Primer" refers to products in the field of coating designed to create a base for the good engraftment of the inks, in this case a UV ink.

A second section D2 is then included, following the first, where the UV ink is distributed;

Finally, there is a third section D3 in which the ink is fixed and dried with UV lamps.

These sections are in succession to each other.

More specifically, with reference to Figure 4, in the first section D1 a special cylinder is provided which, by rotating, laps the cardboard that passes by applying a uniform layer of primer on the print cover, ie the metallized surface 3.

Prior to this phase, an equalizing phase of the cardboard can be advantageously provided, to better make it a planar surface suitable for receiving the Primer.

The Primer used is the result of a research aimed at identifying the correct formula to guarantee a correct anchoring of the UV inks on a metallized surface.

A preferred type of primer was obtained with the following combination of the following substances:

- Aqueous dispersion of acrylic polymers, preferably comprised in a range between 70% and 85%; - Aqueous dispersion of polyethylene waxes, preferably in the range between 4% and 8%;

- Vegetable Anti-Foam, preferably in a range between 3% and 6%;

- Synthetic amorphous silicas, preferably comprised in a range between 5% and 10%;

- Water, preferably in a range between 3% and 6%;

All properly mixed to give the desired result.

The aforementioned primer, therefore, turns out to be a different product from the standard one; in particular, action was taken on the aqueous dispersions of acrylic polymers.

In known art, for example in the packaging production sector, there are numerous types of substance dispensing rollers, such as glues, primers, etc. Any of these types of primer distributor roller can be suitably selected according to the best parameters and therefore usable.

The cardboard with the primer passes through a drying oven, preferably included in the same section D1, in order to make the primer adhere well, and then enters the printing unit D2.

It is in fact important that the primer has a correct degree of drying to optimize the subsequent ink setting.

The temperature ranges for drying of the Primer can go from 40 ° C to 80 ° C and even more preferably from 40 ° C to 70 ° C, therefore with an oven that can be set up to 80 ° C.

In section D2 the actual printing process takes place. The section D2 in fact comprises heads with UV inks and they apply, generally by spraying, this ink on the metallized support 3 reproducing the graphic electronic file chosen for the customer, which electronic file is stored and set in the machine.

Therefore, we can imagine the D2 section as a huge digital printer with UV inks, whose heads distribute the ink according to a predetermined design which is electronically stored in the control processor and which controls the spraying of the ink on the metallized layer according to the predetermined design.

Obviously, the digital printing technology in which the design is electronically loaded and executed is in itself known art and is therefore not further detailed here.

Subsequently, the printed cardboard enters section D3 where it undergoes a fixing and drying treatment of the ink thanks to the action of one or more UV lamps present in this section.

Therefore, as schematized in Figure 5A, the UV ink spraying through special heads 50 is shown, for the realization of the predetermined design. As shown in the following schematic of figure 5B, a series of 60 Ultra Violet (U.V.) lamps provide for the drying of the color.

For example, the power values of the lamps can be between 80-120 W.

The cardboard sheets thus produced are therefore ready for the subsequent and final die-cutting.

The whole process allows printing on a waterproof metallic support with high speeds and above all in line and in a single pass.

According to this process, an excellent quality print is obtained. Furthermore, it is noted that no other printing process with traditional techniques and inks (offset and flexography) would be feasible due to the impermeability of the metallic cover to water-based inks.

The Print Head Group can preferably be four color in number with UV inks with 360 dpi resolution with 4 greyscale.

Preferably the primer drying oven can be at modulable temperature.

Different drying values can be tested on a case-by-case basis.

It is also possible to carry out a continuous feeding of the sheets to be printed with minimum gap, thus optimizing the process.

This methodology described allows customization of the print graphics as a .jpg or .pdf graphic file is easily created specifically for the customer.

There is also the possibility of optimizing productivity and printing speed by increasing the graphic output of the print (insertion of different and / or multiple graphics on a single sheet).

There is also an absence of waiting times and costs deriving from the construction of printing systems (offset and flexographic printing).

Phase 3 of punching allows to obtain the final conformation of the cardboard which is suitably cut.

With this technique it is possible to obtain sheets of corrugated cardboard which, once suitably punched, can shape any type of container including fruit crates, American boxes, etc.

Claims (10)

CLAIMS 1. A cardboard (1) for making a packaging characterized in that it comprises a metallized coating (3) distributed on at least one part thereof and a UV ink print on said metallized coating. A cardboard (1), according to claim 1, in which the printing is digital and a primer is distributed on the metallized coating. A cardboard (1), according to claim 1, in which the sheet of cardboard on which said UV ink printing is carried is composed of at least two superimposed layers and of which the outer layer (10) is metallized and an inner layer ( 30) in paper. A cardboard (1), according to claim 3, in which said outer layer (10) is made of PET Silver (Polyethylene terephthalate) and between the outer layer and the inner layer (30) there is a further intermediate layer (20) in LDPE (low-density polyethylene). A cardboard (1), according to one or more of the preceding claims, comprising one or more die-cuts in such a way as to be able to shape a packaging, for example a cassette or an American box. 6. A cardboard, according to one or more of the preceding claims, wherein said cardboard is a corrugated cardboard, preferably with a single wave. 7. A container characterized in that it is made with a cardboard (1) in accordance with one or more of the preceding claims from 1 to 6. 8. A method for obtaining a carton (1) intended for the formation of a packaging, the method providing for the phase of: - Creation of a cardboard sheet; - Making a print on at least one surface (3) of said cardboard sheet; - Characterized by the fact that the surface intended to be printed has a metallized coating and in which the printing phase takes place through the distribution on said metallized surface of a U.V. 9. A method, according to claim 8, in which a subsequent phase of treatment of the U.V. ink is provided. distributed on the surface (3) through irradiation with one or more ultra violet (UV) lamps (60). 10. A method, according to claim 8 or 9, in which prior to the phase of distributing the U.V. a primer distribution step is provided on the surface intended to receive said ink, preferably after the primer distribution step a primer drying step is further provided, for example in a suitable drying oven.