EP4094943A1

EP4094943A1 - Transfer adhesive element of improved type and related printing process

Info

Publication number: EP4094943A1
Application number: EP22020215.4A
Authority: EP
Inventors: Stefano SCALDAFERRO
Original assignee: Multi Griffe Srl; Stand Up Srl
Current assignee: Multi Griffe Srl; Stand Up Srl
Priority date: 2021-05-25
Filing date: 2022-05-10
Publication date: 2022-11-30
Also published as: IT202100013514A1

Abstract

The Invention reveals a hot transfer printing method in which a substance imparting an adhesive property is first deposited on a substrate and then transferred by heat to a surface to be printed without the elements of colouring and pigmentation, which will be added later during the printing process.

Description

Technical Field

The Invention is revealed within those printing techniques that use graphic elements called "Transfer" which are suitably adhered to surfaces by heat or other physical processes.

Background Art

The use of sheets or ribbons of specific materials, also called "Transfer", is already known in the State of the Art of printing techniques. These media contain graphic elements and/or pigmentations of various colours which, when heated and placed in contact with adequate pressures on selected surfaces, allow the graphic elements present there to be transferred, thus realizing the printing process.
In Prior Art IT 102021000004850 deposited by the present Inventor, a special support [Fig.1, Prior Art IT 102021000004850 ] is claimed on which the elements constituting the Transfer are deposited in successive stages, support also formed by functional elements that go beyond a mere aesthetic characterization. The above-mentioned support is applied on the surface to be printed by some flexible hot pads similar to those used in pad printing techniques.
The actual graphic element, that comes to move on the surface to be printed, is equipped with adhesive characteristics [Patent Application IT 102021000004850 , chapter 028], such as to allow grip on that surface; however, in printing of special small graphic elements, or in applications on curved surfaces that are difficult to process, this adhesive characteristic of the graphic element of the Transfer may not be particularly suitable.
In this field of application they may also be surfaces made of materials that are refractory to non-strictly specified adhesives, on which it is necessary to work with improved adhesives.
To fix this lack of performances, additional glues are previously added on the surface to be printed, manually or by dedicated machines; nevertheless, this external process to that of the application of Transfer greatly slows down a production line and makes the entire printing process uneconomic.
In Prior Art IT 102021000004850 is also claimed the possibility of applying these specific glues on the graphic element of the Transfer itself, even if this solution does not include all the possible variants of a Transfer graphic print, for example the one in which the above-mentioned print is constitute only by a pigment and not by a graphic element provided with its own physicality and consistency.
The Application DE302274 show a pad printing process for a graphic element placed on transfer support, made by pressure and high temperature; the Application EP2048001A1 show also a transfer element printing process while the Application US7906189B2 show a transfer element wherein there are a different kind of layer with adhesive and chromatics features. Such applications however don't reveal further technical elements to improve the printing process.
The purpose of the present Invention is to claim a new printing system and an improved Transfer-type Device which can simplify and make more efficient the printing process in particular fields of application where high performance, high productivity, short processing times and a large integration in industrial processes are required.

Summary of Invention

The Invention reveals a new Transfer device that brings together some refined features aimed at increasing press performance, productivity and speed in industrial pressing processes. All of this is possible thanks to the realization of a Device in which the substance imparting the adhesive property is first deposited in a substrate and then transferred by heat from the above-mentioned support to the surface to be printed without the elements of colouring and pigmentation, which will be added later during the printing process.
According to the idea of the Invention, an additional pigmented sheet is adhered on top of the adhesive layer, anchored to the surface to be printed and which will retain, from the said pigmented sheet, the colourings that will create the desired element, colourings that will only adhere on the section of surface circumscribed by the adhesive itself.
Further features of the Idea, result of the Invention presented in the chapter DESCRIPTION OF EMBODIMENT allow, moreover, a faster printing process and oriented towards new Industry Processes 4.0. In the end, the Invention reveals a chromatic technique that allows a higher quality of details and the overall aesthetic effect of the Transfer element.

Advantageous Effects of Invention

The main advantages result of the idea of the Invention can be summarised as follow:

a. the Invention allows highly adhesive Transfer prints for a variety of surface,
b. the Invention allows a particularly fast printing process,
c. the Invention enables a more accurate colour management of the Transfer, with a higher level of performance than the State of the Art, thanks to the use of various pigmented sheets on the market,
d. the Invention is compliant with Industrial Process 4.0,
e. the Invention is compatible with State of the Art printing machinery.

Brief Description of Drawings

The drawings table is integrated in the documents of this application in order to exemplify the characteristics of the Invention, even highlighting variations in the application described therein; in this case:

Fig.1
[fig.1] reveals Prior Art IT 102021000004850 consisting of the construction layers of the Invention and the removable protective sheets,
Fig.2
[fig.2] reveals a sheet and a support ribbon according to the idea of the Invention
Fig.3
[fig.3] reveals the Release deposit according to the idea of the Invention,
Fig.4
[fig.4] reveals the deposit of the adhesive element, according to the idea of the Invention,
Fig.5
[fig.5] reveals the Transfer replication on the surface of the sheet and of the support roll according to the idea of the Invention,
Fig.6
[fig.6] reveals the deposit of the unique visual recognition element on the sheet and of the ribbon according to the idea of the Invention,
Fig.7
[fig.7] reveals the unique visual recognition element according to the idea of the Invention, equipped with a chemical temperature gauge,
Fig.8
[fig.8] reveals the initial process of printing the adhesive element of the transfer on the upper of a shoe, according to the idea of the Invention,
Fig.9
[fig.9] reveals the final process of the transfer printing on the upper of a shoe according to the idea of the Invention,
Fig.10
[fig.10] reveals the outcome of the Transfer printing result of the idea of the Invention,
Fig.11
[fig.11] reveals the Transfer, result of the idea of the Invention, supplemented by an additional graphic element by means of screen- printing,
Fig.12
[fig.12] reveals the Transfer, result of the present Invention, applied on the outer sole of the shoe by means of a mechanical punch.

Description of Embodiments

The description of the different forms of realization of this Invention is revealed here for illustrative purpose and it is not intended to be completely exhaustive or limited to the form of realization described therein. Moreover, all possible modification of an obvious nature of the Invention and its scope, put in place by persons experienced in the field, do not limit the terms of protection of the license itself.
The length and pressure parameters in this Description comply with the International System of Unit of Measurements (S.I.). In this Description, the term "Transfer" is used to identify either the Device (or part of it) or the type of printing which employs the above-mentioned transferable elements from a support to a working surface.
According to the form of realization of the Invention, a support of suitable material, preferably Polyester, Polyurethane or Polypropylene, is prepared in the form of a thin sheet that acts as a support (20) for subsequent elements and subsequent processing that constitute the improved Transfer printing Device.
The main element that constitutes the idea of the Invention is a deposit, on the support sheet, of a suitable transparent adhesive thermoplastic resin, slavishly identical in shape to the shape of the graphic element to be printed on the chosen surface. So, according to the idea of the Invention, the adhesive element of the Transfer is separately processed from the Transfer complete with chromatic characteristics.
The thickness of the material, Polyester, Polyurethane or Polypropylene, constituting the support sheet, can vary from 35um (10^-6 meters) to 150um (10^^-6 meters), that is a thickness that allows adequate flexibility but also adequate robustness in relation to the different fields of use. Preferably, this thickness ranges from 50um (10^-6 meters) to 100um (10^-6 meters).
This support sheet can be profitably realized in the form of a continuous ribbon wound on a reel (21) because the above-mentioned layout is typical and in use in graphic printing machines in industrial production processes, for example pad printing or transfer printing.
On one of the two surfaces of the support sheet is then added a layer of treatment named "Release", made up of a chemical formulation with synthetic cross-linked resins by Ultraviolet rays (30)(31).
The Release material is specifically designed to ensure that the transparent adhesive thermoplastic resin element that will be added upon it later can be quickly detached during the printing process, on average in a time between 300ms (10^-3 seconds) and 800ms (10^-3 seconds). This makes the printing process extremely fast. The Release material layer, then, allows the detach of the transparent adhesive thermoplastic resin element while the temperatures generated by contact with the appropriate mechanical printing medium, for example a heated and flexible pad or a metal punch, are still high.
According to the form of realization of the Invention, upon the Release material layer is added the transparent adhesive thermoplastic resin element itself. The perimeter shape of the resin deposit will slavishly follow that of the graphic element to be printed (40) (41), thus creating a sort of adhesive base for the pigments that will be added by means of the subsequent stages of the process resulting from the present Invention. The transparent adhesive thermoplastic resin element illustrated in Fig.4 has been highlighted in order to be visible in the drawing table of this Application.
According to the form of realization of the Invention, "n" Transfer elements are profitably realized, side by side (50) (51), made up of the transparent adhesive thermoplastic resin and the underlying Release material layer, by means of the technique revealed in chapters [0030, 0031, 0032, 0033, 0034 and 0035], for the entire length of the support sheet, even in the form of wrapped ribbon (52) (53).
According to the form of realization of the Invention, a unique visual recognition element, or Marker (60) (61), is inserted in each Transfer element. This element identifies the exact position of the Transfer on the support sheet and it is used by the printing machine to position the same sheet correctly on the surface to be printed, that is to say consistently with the spatial coordinates inserted in the printing machine programming.
According to a further form of realization of this Invention, the Marker element can contain information encoded using alphanumeric or graphic characters, for example using a QR code technology, such as to allow an interaction with the machine and therefore with IT management of industrial processes. Such integration is typical of Industrial Processes 4.0. An example is given by the procedure for the exact identification of the Transfer to be printed, encoded in the Marker element and read by the printing machine by means of sensor and/or camera.
According to the form of realization of the Invention of chapter 0037 the Marker element can also incorporate passive or active technical solutions, even for mono or bidirectional data communication between the printing machine and Transfer according to the idea of the Invention, for the control of the printing process. Moreover the above-mentioned Marker element can integrate a passive chemical temperature sensor for storing the maximum temperature reached by the Transfer during the printing process; this allows the acquisition of industrial process data suitable for printing quality control.
In Fig.7 two Marker elements are visible, that indicate different temperature ranges of the completed printing process: The "x" element (71) shows an indication given by the compliant colour type while the "y" element (70) shows an indication given by the non-compliant colour, for example out of the temperature range allowed by the pre-defined printing process.
According to the form of realization of the Invention the Transfer, result of the present Invention, is then applied (82) on the chosen surface by means of a profitable mechanical mean of contact (for example a flexible and heated tab, a mechanical punch, a heated plate etc.).
PROCEDURE FOR APPLYING THE DEVICE: as an example in Fig.8 the surface to be printed is represented by the upper of a shoe. In Fig.8 the Transfer, which is the subject of the present Invention, is made in the form of a support ribbon wound onto rotating spools loaded during the machine setup, that is provided with suitable traction engines that allow unwinding/rewind the support sheet containing the Transfer, that is the transparent adhesive thermoplastic resin deposit upon the Release material layer. In the same Fig.8 the transparent adhesive thermoplastic resin element illustrated has been highlighted for the purpose to be visible on the drawings table of this Application; its correct position on the support sheet is, indeed, the opposite surface to the one visible in Fig.8.
According to the idea of the present Invention, with the printing process put in place by the mechanical means the transparent adhesive thermoplastic resin element will be transferred to the upper of the shoe (90). The transparent adhesive thermoplastic resin element portrayed in Fig.9 has been highlighted for the purpose to be visible on the drawings table of this Application.
By exploiting the characteristics of the Release treatment applied on the support ribbon result of this Invention, this part of the process, consisting of the detachment of the adhesive resin, takes between 300ms and 800ms, thus considerably speeding up the entire process.
According to the idea of the Invention, at this point the printing machine, by means of special translating devices, moves the Transfer ribbon from the working position and put in the same working area a pigmented sheet, already known on the State of the Art printing technology.
According to the idea of the Invention at this point the process by contacting the printing mechanical means is repeated using the pigmented sheet. The colouring present on this sheet (91), under the pressure of the printing mechanical means (92) will be permanently transferred to the area defined by the transparent adhesive thermoplastic resin (90), thus completing the printing of the Transfer on the shoe upper (100). In Fig.9 the colourings of the pigmented sheet have been made visible in transparency on the opposite side of the sheet to facilitate understanding of the technique according to the Invention; the correct position of the pigmentations on the sheet, in fact, is the opposite surface to the one visible in Fig.9.
The special Release treatment, which allows the detachment of the transparent adhesive thermoplastic resin in times between 300ms and 800ms, can be optionally replaced with a different formulation, already known by the State of the Art, that allows a detachment of the adhesive element from the sheet only when the temperature returns to values consistent with the ambient ones, for example 20/25 c°. This so-called "cold" technique, while not allowing high-speed printing procedures, can nevertheless benefit from the technique described here in terms of precision and print quality. Moreover, pigmented sheets capable of releasing their colourings without the aid of high temperatures can be used, so only thanks to the adhesion of the transparent adhesive thermoplastic resin, thus avoiding the use of heated printing mechanical means.
In Fig. 12 the insole of a footwear assembly (120) is printed using the Transfer of the present Invention (121): A self-propelled mechanical punch (122) exerts adequate pressure on the Transfer, allowing the transparent adhesive thermoplastic resin (123) to adhere to the surface of the insole once it is detached from the Release treatment (124). Then, a pigmented sheet is used (125), that will release the colouring in the area delimited by the adhesive thermoplastic resin, always by the pressure exerted by the same self-propelled mechanical punch. Always in Fig.12 the illustrated transparent adhesive thermoplastic resin element and the colouring of the pigmented sheet have been highlighted in transparency to be visible in the drawings table of the present Application; the correct position is, in fact, on the opposite surface to the one visible in Fig.12.
The main use of the Transfer, result of the present Invention, takes place with transfer printing machines. Nevertheless, any mechanical means of contact, even when not designed for printing but capable of exerting adequate pressure between the Transfer and the surface to be printed can be successfully employed, allowing fitting the Device of the present Invention in more fields of application.
The use of pad printing device with accentuated flexibility characteristics is preferable when the surface to be printed is not perfectly flat, that is curved or irregular.
In another form of realization of the Invention the adhesive thermoplastic resin may be formulated with a particular colouring, so not transparent but with a range of pigmentations such that it is a part of the overall colour effect of the Transfer printing according to the idea of the invention, when subsequently completed using the pigmented sheet. According to this further form of realization of the Invention, this technical variant allows a sort of realization process of the colours of the Transfer through the use of two overlapping pigmentations levels, one included in the adhesive thermoplastic resin and the other in the pigmented sheet, in order to obtain an overall graphic effect with more resolution, sharpness and quality in the colours, as well an improved resistance to abrasion and wear.
According to a further form of realization of the present Invention, the deposit of the adhesive thermoplastic resin element on the support sheet may coincide with a further deposit by screen printing or other similar technique, with additional graphic elements (110) (111) which, together with the adhesive thermoplastic resin, complete the Transfer element. These additional graphic elements will be transferred to the surface to be printed during the printing process as they have a special adhesive characteristic when processed by the printing mechanical means.

Industrial Applicability

The Device, result of the present Invention, finds application in all those Transfer type printing techniques used today in a wide range of industrial and craft activities, particularly in leather and fashion, footwear and its accessories, textiles etc. The technique revealed in this Invention, however, is profitably applicable in all areas of graphic design at a professional level on many types of surfaces, both synthetic (plastics, for example) and natural (leather, glass etc.).

Citation List

Citation List follows: no citations.

Patent Literature

PTL1: IT 102021000004850
PTL2: DE3022744A1 ,
PTL3: EP2048001A1 ,
PTL4: US7906189B2

Claims

Hot transfer printing element consist of a carrier film made of Polyester or Polypropylene or Polyurethane with a thickness between 35 um (10^-6 meters) and 150 um (10^-6 meters), preferably between 50 um (10^-6 meters) and 100 um (10^-6 meters), also wrapped in a reel as continuous tape wherein:
a. a layer of "Release" material (30)(31) is deposited above one of the two surfaces of the carrier film, consist of a chemical formulation made of synthetic resin with reticulation process activated with Ultraviolet ray, with a release property activated in a time frame between 300 ms (10^-3 seconds) and 800 ms (10^-3 seconds),

b. a transparent adhesive thermoplastic resin is deposited on top of the Release material layer with a mirrored shape to a graphic element to be printed (40)(41),

c. a visible Marker (60)(61) is imprinted on the carrier film near the deposit of transparent adhesive thermoplastic resin,

d. the Release treatment deposit, the transparent adhesive thermoplastic resin and the Marker are repeated for the entire length of the carrier film (50)(51).
Hot transfer printing element of the Claim 1 in which the thermoplastic adhesive resin has one or more pigmentations.
Hot transfer printing element of the Claim 1 in which the adhesive thermoplastic resin deposit is integrated with the deposit of one or more further additional graphic elements (110)(111) by means of screen printing or other printing known technique.
Hot transfer printing element of the Claim 1 in which the Marker is composed by an alphanumeric code.
Hot transfer printing element of the Claim 1 in which Marker is composed by a graphic codified element, also QRCode type.
Hot transfer printing element of the Claim 1 in which the Marker is composed by an alphanumeric code and by a graphic codified element, also QRCode type.
Hot transfer printing element of the Claim 1 in which the Marker is integrated by a chemical element measuring temperature.
Hot transfer printing element of the Claim 1 in which the Marker is composed by a monodirectional or bidirectional data communication device with the printing machine, also integrated with an alphanumeric and/or graphic codified code, also QRCode type.
Hot Transfer printing process by means the element of the Claim 1 wherein:
a. the carrier film is positioned above a surface to be printed, so that the adhesive thermoplastic resin and the Release treatment be facing the surface to be printed,

b. a flexible and heated pad puts in contact the carrier film, with the surface to be printed, keeping a pressure,

c. the adhesive thermoplastic resin deposit adheres to the surface to be printed in a time frame between 300ms and 800ms, separating itself from the Release treatment,

d. the heated flexible pad moves away from the carrier film and the printed surface,

e. a pigmented tape is positioned above the adhesive thermoplastic resin print, so that the pigmentation of the tape is facing the printed adhesive thermoplastic resin,

f. the flexible and heated pad puts in contact the pigmented film, with the adhesive thermoplastic resin print,

g. the pigmentation of the tape is transferred to the adhesive thermoplastic resin print,

h. the heated flexible pad moves away from the printed surface.
Hot Transfer printing process of the Claim 9 wherein the heated flexible pad of paragraph (ii) (iv) (vi) ed (viii) is replaced with other any mechanical element that produce a pressure between the surface to be printed and the Transfer of the Claim 1.