EP1207046A1 - Thermal transfer system with transfer indicator - Google Patents

Abstract

The heat transfer, to transfer an image on to a substrate (4), has a front side (2) to bond to the substrate and a rear side (3) which peels away. When the peelable rear side has reached a given temperature, for the transfer system (1), a visible thermal indicator (5) is shown through a color change. The heat transfer system, to apply an image to a substrate, has a thermal indicator which, when cold (10), has two different color zones as an outer zone and a symbol zone (8). The characteristic parameters for the transfer conditions are pressure, temperature and time. The thermal indicator is integrated into the printing ink at the rear side of the transfer, using a heat-reacting green flexoprint ink and preferably INNOVA 62--TC-251-7110. On heating for the image transfer, the color of the outer zone completes the coloring of the symbol zone, or vice versa. Reference surfaces are at the rear side, next to the thermal indicator, to show the heat development by color nuances. The front side of the transfer is a fusible polymer layer or polymer film. The rear side of the transfer is covered by a varnish overprint, to increase thermal conductivity and prevent smearing.

Description

The invention relates to a thermal transfer system with a thermal indicator, which in the field of thermal transfer foils, ink-jet substrates or also xerographically transferable transfer foils for printing on a carrier substrate can be used.

From WO 98/30749 an ink jet transfer system has become known as well as a Process for its manufacture and use for a printing process. In The international application will use an inkjet transfer system or a Transfer printing system described, which a high level of wash fastness and Has color fastness and good ecological behavior, furthermore a process for its Production and use for a printing process using the inventive Ink-jet transfer system. The ink jet transfer system according to the invention comprises a carrier material, a hot-melt layer applied to the carrier material and at least one ink receiving layer, at least one ink receiving layer comprises a mixture of a highly porous pigment and a binder, the Molecules of the pigment and optionally the binder and optionally the Hotmelts for the formation of chemical bonds with the dye molecules of the Ink are capable.

DE 197 31 498 A1 relates to a method and an apparatus for application a stable printed image on a textile substrate. It will be the following Go through the listed process steps:

A multilayer ink transfer sheet is provided which has a Carrier layer, a removable solution layer positioned on the carrier layer, and has an ink-receiving layer positioned on the solution layer wherein the ink-receiving layer has at least one quaternary ammonium salt. Furthermore, an ink composition is used which is at least one anionic Has colorants and an ink carrier. The ink composition is on the ink-receiving layer of the ink transfer sheet is applied to a printed one Form image on the ink transfer sheet, with the anionic colorant in the Ink composition to the quaternary ammonium salt is bound to the Colorant to connect with the ink transfer sheet. After that it will Ink transfer sheet placed on the textile substrate so that the Ink receiving layer of the ink transfer sheet in contact with the textile substrate stands. Thereafter, heat is generated, which is applied to the ink transfer sheet merges while the ink transfer sheet is positioned on the textile substrate such an amount sufficient to cause the The solution layer and the ink-receiving layer adhere to the textile substrate thereon. The carrier layer is then removed from the ink transfer sheet to remove the Separate solution layer from the carrier layer, the solution layer and the Ink-receiving layer adhered to the textile substrate such that the printed image is transferred to the same.

US 5,501,902 relates to a printable material. The material has a first and a second surface, the printable material containing a first layer which represents the first surface and comprises a second layer comprising the second Surface defined. The second layer contains particles of a thermoplastic polymer, whose largest dimensions are less than 50 microns, and 10 to 50 wt .-% one film-forming binder based on the weight of the thermoplastic polymer. If the second layer has reached a temperature between 65 and 180 ° C, this is suitable printable material as heat transfer material. The second layer preferably contains 2 to 20% by weight of a cationic polymer based on the weight of the thermoplastic polymer. Other components of the second layer can for example 0.2 to 10% by weight of a material influencing the color viscosity, further 0.5 to 5 wt .-% of a weak acid and other ingredients. It can definitely one or two additional layers of one when exposed to heat softening material may be provided between the first and second layers the heat transfer of the second layer transferring an image to be printed to Support textile substrate.

When transferring print images to textile substrates e.g. when ironing on T-shirt foils on textiles, the foils are applied by feel. When transferring of the print subject on textile substrates have the transfer time, the transfer temperature as well the pressure prevailing during the transfer has a decisive influence on the achievable quality the transfer print as well as the quality of the transferred print image. When ironing on the heat source plays a role in printing images on textile substrates, e.g. a commercial one Irons play a crucial role. The operating temperatures of irons can fluctuate between 140 ° C and 240 ° C, even if the iron is on the same Textile substrate is set. If the iron is weak, ironing will take a lot longer than those with higher heating output. This means that identical digits of a Substrate mechanically stressed longer by circular motion of an iron become. Also important is the pressure with which the iron handling the iron to the iron during the transfer process Textile substrate presses. Finally, the transfer time is important, often only is adhered to at will and is usually too short and often too long.

In view of the solutions known from the prior art as well as that shown technical problem, the invention is based on the object To create thermal transfer system, which the existence of optimal transfer conditions displays.

According to the invention the object is achieved in that a transfer system for Transfer of an image onto a substrate, a front side adhering to the substrate and a back peelable from the front side, the one facing the substrate Front by heating by means of a heat source on the substrate to be printed adheres and the back is removable from the front adhering to the substrate the removable back of the transfer system when the optimal one is reached Transfer conditions a visible color change thermal indicator is applied.

The advantages that can be achieved with the solution according to the invention are above all in it behold that the thermal indicator applied time pressure and that in the Transfer system introduced heat reacts and thus an application of the Front of the transfer system applied print image with optimal Transfer systems allowed regardless of subjective impressions of the user. Parameters of the heat source such as strong temperature fluctuations as well as that Scroll through application instructions of transfer systems during transfer of the melting polymer layer applied to the front of the transfer system can be omitted, the person using the transfer system also finds Pressure applied during the transfer process is no longer considered the start of the back of the transfer system. The user only has that Color change of the one proposed on the back of the invention Observed transfer system applied thermal indicator, which at optimal Transfer conditions with regard to preheating time, elapsed time and Applied print changes its color to a final shade that is next to one Color-changing thermal indicator on the back of the invention configured transfer system is applied.

In a further embodiment of the idea on which the invention is based, the Thermal indicator in the cold state on two different color areas, which in the Cold state of the transfer system are colored red or green, to name examples.

The outer area of the thermal indicator, which is an inner symbol area of the Can enclose the thermal indicator in a ring, for example is colored in green, whereas - to give an example - designed as an iron symbol Symbol area can be colored red. The means of the on the back of the Transfer system applied thermal indicator visually displayable, optically perceptible optimal transfer conditions are characterized by the characteristic Parameters pressure, temperature and the exposure time of the heat source are shown.

In a particularly preferred embodiment, the thermal indicator can be printed in a printing ink be integrated with the the back after heating the front of this is removable, can be printed using the flexo process. The thermoreactive For example, flexo ink can be INNOVA 62-TC-251-7110 (green), whereas the symbol area of the thermal indicator surface in a different one from this Color, for example red, can be colored.

When the thermal indicator is warmed up, it performs the symbol area of the Thermal indicator surface 6 enclosing a color change in the outside area Coloring of the symbol area so that the thermal indicator is seen as a whole Color nuance of the symbol area assumes. It is equally possible that the Symbol area in the warmed state of the thermal indicator changes color and takes on the color of the outside. The decisive factor is the fact that a Color change visible to the user on the thermal indicator on the The back of the transfer system configured according to the invention takes place to the user of the transfer system visually indicates that now the optimal transfer conditions available. Has the thermal indicator completed its color change, i.e. lies one in with the same color, the user can see the back, i.e. the silicone paper from the melted polymer layer adhering to the substrate pull it off. A thermoreactive color can also be used to facilitate the indication thermal indicator containing a similarly configured pattern of the thermal indicator be applied, a reference color INNOVA 62-TC-251-001, which is already in the Cold state the final nuance of the one provided with a thermoreactive color Thermal indicator can assume that this after the color change, i.e. reaching the transfer temperature finally assumes. This is the time to pull the Back of the transfer system from the adhesive layer adhering to the textile substrate slightly closed determine. You can choose between the final shade of the thermal indicator and the reference color subtle differences remain; the final shade is therefore to be understood as a directional shade shade.

The thermoreactive flexographic ink and its sensitivity to heat, time and Pressure is the polymer layer to be transferred, i.e. the actual textile transfer system Voted. This is particularly noteworthy with regard to the melting range of the Polymer layer, which removes the back from the silicone paper used right time, i.e. determined by the existence of the optimal transfer time.

The front of the transfer system according to the invention can be used as a melting one Polymer layer or polymer film may be formed, whereas the back of the transfer system according to the invention can be obtained as a silicone paper.

The transfer system proposed according to the invention can be used for the transfer of Print subjects, print images or other motifs on substrates such as Textile substrates in the form of thermal transfer foils, ink-jet papers or Use transfer foils that can be ironed on xerographically. In the invention proposed transfer system, it does not matter in what form the thermal indicator is applied. This can be done by means of flexographic printing, spraying, Pouring, steaming, by means of gravure printing using a powder coating or UV curing.

The invention is explained in more detail below with the aid of the drawing.

Figuren 1, 2

zwei nebeneinanderliegende Thermoindikatoren auf der Rückseite eines Transfersystems, wobei einer der Indikatoren als die Endnuance des Farbumschlages dienendes Referenzmuster ausgebildet ist,

Figur 3

einen erfindungsgemäßen Thermoindikator in teilweise erwärmtem Zustand,

Figuren 4, 5

einen erfindungsgemäßen Thermoindikator in teilweise, jedoch noch nicht vollständig durchgewärmtem Zustand und

Figur 6

den erfindungsgemäßen Thermoindikator in im wesentlichen durchgewärmten Zustand.

It shows:

Figures 1, 2

two side-by-side thermal indicators on the back of a transfer system, one of the indicators being designed as a reference pattern serving as the final nuance of the color change,

Figure 3

a thermal indicator according to the invention in a partially heated state,

Figures 4, 5

a thermal indicator according to the invention in a partially, but not yet fully warmed, and

Figure 6

the thermal indicator according to the invention in a substantially warmed-up state.

From the representations according to Figures 1 and 2 go side by side on the back of a transfer system printed thermal indicators, one of which is a contains thermoreactive color and the other contains the final nuance of the color change that is running out on the reactive indicator with a reactive color.

The proposed according to the invention follows from the representation according to FIG Transfer system 1 in more detail. The front 2, which is the surface of a substrate For example, assigns a textile substrate 4 is as an adhesive layer, preferably as Polymer layer or polymer film formed. The back 3 of the invention Transfer system 1 preferably comprises a silicone paper, on the top of which according to the 1 shows a thermal indicator 5 configured here in a circle with a Temple symbol 8 is printed. The thermal indicator 5 is preferably in a Integrated printing ink, for example by means of the flexographic printing process on the Back 3 of the transfer system 1 can be printed.

In addition to the circularly configured thermal indicator surface 6 selected here this also another full-surface geometric pattern, for example an ellipse or have a bold font or other symbolism. It is crucial that the Thermal indicator surface 6 is attached to the top of the back 3 and in the Is able to provide the user of the transfer system 1 configured according to the invention noticeable discoloration.

The thermal indicator 5, from the illustration according to FIG. 5 as a circular configuration Removable, contains a thermal indicator surface 6, which by an indicator limit 7 is enclosed. In the middle of the circularly configured thermal indicator surface 6 shows a symbol 8, which can be designed, for example, as an iron. Stronger, more nuanced strips 9 are formed on the iron.

In the unheated cold state of the thermal indicator 5 shown in FIG Symbol area 8 enclosing outer area 11 of the thermal indicator 5 colored green, just to give an example, while the symbol area 8, that of the outside area 11 enclosed, is for example in red 12 is obtained (see FIG. 2).

In this state, i.e. in the cold state 10, the invention Thermal transfer system 1 on the top of a substrate, preferably one Textile substrates 4 placed. In the non-heated state 10 there is a clear perceptible contrast of the coloring of the outer area 11 of the thermal indicator 5 in the In contrast to the symbol area 8 enclosed by the outer area 11 Thermal indicator surface 6.

A thermal indicator according to the invention is shown in FIG. 3 partially warmed up.

In this state, i.e. in a partially heated state of the transfer system 1, designated by reference numeral 13, is by a on the top of the back 3 of the Transfer system 1 provided an iron heating the transfer system consisting of front 2 with adhesive layer and removable back (silicone paper) performed. By exposure to heat over a certain period of time and from Users on the heat source, i.e. the pressure exerted on the iron heats up Transfer system 1, consisting of front 2 and back 3. The thermoreactive color of the thermal indicator 5 takes in the partially heated state 13 of the thermal indicator 5 a discolouration 14 which corresponds to the coloration of the Symbol area 8, represented here by an iron, corresponds. In Figure 3 shown state, however, the thermal indicator surface 6 is clearly perceptible in a discolored indicator area 14 and a still uncolored indicator area 15 in the Outside area 11 of the thermal indicator surface 6 divided. This means that at the entire thermal indicator surface 6 the optimal conditions under which a transfer the front 2 should be made on the top of the textile substrate 4, have not yet been fully met. This means that the user chooses the heat source, i.e. the iron, further to the transfer system 1 proposed according to the invention must act in order to achieve the optimal transfer conditions.

4 and 5 are configured according to the invention Transfer systems 1 emerge, the thermal indicators 5 a further, but not yet have fully warmed up.

In comparison to the representation according to FIG. 3, the representation according to FIG partially warmed condition 13 substantially reached discolored indicator area 14 more extensive, compared to that with reference numeral 15, still undyed Surface of the outer area 11, which is not yet the final shade of the Symbol area has reached 8. Here is the partial warming of the Thermal indicator surface 6 compared with the representation of the thermal indicator 5 Figure 3, however, advanced so that the heat source only for a short time in Area of the thermal indicator 5 can act to optimal transfer conditions achieve the back 3 of the adhesive or carrier layer 2 of the transfer system 1 can be deducted.

The illustration according to FIG. 5 also shows a thermal indicator surface 6 in partially warmed state 13 by two in different shades of color trained areas is marked. With reference numeral 14 is the discolored Indicator area, preferably referred to lying in the outer area 11, while with Reference number 15 is the still uncolored region of the outer region 11 of the Thermal indicator surface 6 is characterized, which continues to heat preferably in circular movements on the back 3 of the thermal transfer system 1 is to be supplied. In the state shown in Figure 5, the thermal indicator 5 shows the user that a further heat supply to the rear 3 of the transfer system 1 is required to to achieve optimal transfer conditions that are not yet complete in this state available.

From the representation according to FIG. 6, one proposed according to the invention can be seen Thermal indicator 5 on the back of a transfer system 1, which in the has essentially reached a completely warmed-up state.

The completely warmed-up state of the thermal indicator surface 6 is included Reference numeral 16 denotes. In this state, due to the exposure time Heat source, the temperature of the heat source and that applied by the user Pressure of the outer region 11 of the thermal indicator surface 6 a complete Discoloration 17 accepted. This is caused by the thermoreactive color in the Printing ink of the back 3 of the transfer system 1 is included. The completely discolored, The area surrounding the symbol area 8 preferably takes on in the discolored state 17 the final shade 18 of the coloring of the symbol area 8; this means that the Thermal indicator surface 6 of a substantially contrasted with each other two-tone coloring according to the representation of Figure 1 or 2 in a uniform colored surface 18 has passed. This color change 19, from a contrasting The user of the perceived and displays transfer system 1 configured according to the invention, that the optimal transfer conditions now exist, i.e. that pulling the Back side 3, which is preferably provided as a silicone paper, from the front side 2 of the transfer system 1 can take place.

A thermoreactive color with which the back 3 of the proposed according to the invention Transfer system 1 can be colored, is e.g. INNOVA 62-TC-251-7110, green the SCIPA AG, Switzerland. In addition to the example of a selected here thermoreactive color, of course other color shades can be used, their Criterion is based on the selected coloring of the symbol area 8 in the cold state 10 to distinguish the thermal indicator 5 by contrast. What final nuance in the end a warmed-up thermal indicator surface 6 on the rear side 3 of the invention proposed transfer system 1 is irrelevant. The only thing that matters is that between the cold state 10 of the thermal indicator surface 6 and completely warmed-up thermal indicator surface 6 an optically perceptible color change 19 occurs.

With the solution according to the invention, transfer systems 1 can be scrolled in without long Simply apply instructions to the surfaces of textile substrates 4. A Taking into account the achievable temperature of the heat source in the form of a Iron is no longer required. It should be noted that the iron temperatures can fluctuate between 140 ° C and 240 ° C with the same selected heat symbols, so that a temperature difference of up to 100 ° C can occur. Weakness Heat sources require a much longer exposure time compared to stronger ones Heat sources. Furthermore, by the objectively optimal transfer conditions indicating Thermal indicator surface 6 a decoupling of the transmission quality from applied pressure can be achieved by the user. The thermal indicator surface 6 takes into account the individual transfer time of the temperature of each Heat source or the pressure applied during application after reaching the optimal transfer conditions before his color change 19. It is not one Specification time, a restriction of the pressure level to be applied is required. ever according to individual parameters, transfer time, temperature of the iron as well Applied printing, the color change 19 takes place in the thermal indicator surface 6 whenever all transfer criteria have reached their optimum.

For example, the color change 19 into the final shade 18 from green to red 20 seconds, using a heat source in the form of an iron of 1400 watts of power, with which the back 3 of the transfer system 1 in orbiting Movements can be coated. This can make the indication easier can be achieved that a thermal indicator 5 provided with a thermoreactive paint a reference surface 20 can be assigned, which is already printed in the final nuance 18 which the thermal indicator surface 6 in the fully warmed-up state 16 reached. So it is even easier for the person handling the transfer system 1 Time of the existence of optimal transfer conditions by comparing the To determine the thermal indicator surface 6 with the reference surface 20.

The application of the thermal indicator 5 by means of the flexographic printing process is in practice very feasible and easy because the thermoreactive substances in one Flexographic printing ink are integrated. This way the back of the The easiest way to equip silicone paper with a thermal indicator surface 6.

The thermal indicator 5 can be, for example, by means of two clichés in one Print process. With one of the clichés, the outer surface of the Thermal indicator surface 6 are printed, which is the thermoreactive flexographic printing ink contains. The inner surface of the thermal indicator 5 can be printed using the second cliché become, i.e. the area that contains the reference color shade (beige) and with the Iron symbol 8 is provided. The assignment of the respective clichés with outside and Inner surface of the thermal indicator surface 6 can also be in reverse order be made. In addition, it is also possible to use any symbols 8 only with the thermoreactive color and any symbols in parallel only with the reference color be printed. Accordingly, thermal indicators 5 and Reference areas 20 printed. However, it is also possible to use only symbols with the to print thermoreactive color and give the user a separate reference card or to hand over a separate reference print on normal paper, which with a Reference surface 20 are printed, which has the color tone which the thermal indicator 5 on the textile substrate 4 after supplying heat and reaching the optimum Finally accepts transfer conditions after the color change 19.

It is irrelevant whether the thermal indicator 5 according to the flexographic printing process, the Spraying, pouring, steaming or by gravure printing on the Transfer system is applied according to the present invention. In addition to the Powder coating and UV curing are also possible.

The reference surface 20 will not always take on the same color as that Thermal indicator surface 6. The final nuances of the reference surface 20 as well as the The final nuance of the thermal indicator 5 can have subtle differences; in this sense the reference surface 20 is to be understood rather as a directional shade. The reference surface 20 shows the discoloration in the direction of which is present on the thermal indicator 5 in contrast, the optimal transfer conditions set the corresponding discoloration to the reference surface 20, the state of which does not change when heated Thermal indicator 5 is irreversible thanks to the integrated thermoreactive color irreversible color change.

To increase the thermal sensitivity of the thermal indicator 5, especially in Temperature range down, can be according to the back 3 of the transfer system 1 of the present subject matter of an additional transparent lacquer layer muster. This increases the sensitivity of the thermal indicator 5 considerably. The Overprint varnish layer, which the additional transparent varnish layer also refers to is fulfilled in addition to the function of increasing the thermal sensitivity and one Improvement of the heat transfer between the sole of an iron and the Surface of the transfer system another task. The additional transparent Lacquer layer protects the back of the silicone paper through its training as smear-resistant lacquer layer against contamination. The soles of less high quality Irons are not made of polished chrome steel, but of cheaper steel or Aluminum, which are made with a higher surface roughness. Such designed Surfaces can result in the print patterns being mechanically scratched and tend to smear.

With an additional transparent lacquer layer, mechanical scratching is the key Back of the thermal transfer system withdrawn the basis.

LIST OF REFERENCE NUMBERS

1

transfer system

2

Front (adhesive layer)

3

Removable silicone layer on the back

4

textile substrate

5

Thermo indicator

6

Thermo indicator surface

7

indicator limit

8th

indicator icon

9

strip

10

Cold transfer system status

11

Outdoor indicator (green)

12

Icon area (red)

13

partially warmed up condition

14

discolored indicator area

15

uncolored indicator area

16

warm condition

17

completely discolored outdoor indicator

18

End nuance indicator surface

19

changed indicator color

20

reference pattern

Claims (15)

Transfer system for transferring an image to a substrate (4) with a front (2) adhering to the substrate (4) and a back (3) which can be peeled off from the front (2), the front (2) facing the substrate (4) by heating adheres to the substrate (4) to be printed with a heat source and the rear side (3) can be removed from the front side (2) adhering to the substrate (4), characterized in that on the removable side (3) of the transfer system (1) a If the optimum transfer conditions are reached, a visible color change (19) is applied to the thermal indicator (5). Transfer system according to claim 1, characterized in that the thermal indicator (5) in the cold state (10) has two different color areas (11, 12). Transfer system according to claim 2, characterized in that the different color areas are an outer area (11) and a symbol area (8, 12). Transfer system according to claim 1, characterized in that the parameters characterizing the transfer conditions are pressure, temperature and time. Transfer system according to claim 1, characterized in that the thermal indicator (5) is integrated in the printing ink on the back (3) of the transfer system (1). Transfer system according to claim 5, characterized in that the printing ink is a thermoreactive flexographic printing ink. Transfer system according to claim 5, characterized in that the printing ink is the color INNOVA 62-TC-251-7110, green. Transfer system according to claim 2, characterized in that in the heated state (13, 16) the outer area (11) of a thermal indicator surface (6) changes color (19) in the coloring of the symbol area (8, 12). Transfer system according to claim 2, characterized in that in the heated state (13, 16) the symbol area (12) of a thermal indicator surface (6) changes color (19) in the coloring of the outer area (11). Transfer system according to claim 1, characterized in that, adjacent to the thermal indicators (5), reference surfaces (20) are provided on the rear side (3) of the transfer system (1), which correspond to a color shade (18) of the thermal indicator surface (6) into which these turns over when heat is applied. Transfer system according to claim 1, characterized in that the front side (2) of the transfer system is designed as a melting polymer layer / polymer film. Transfer system according to claim 1, characterized in that the rear side (3) of the transfer system (1) is coated with an overprint varnish layer which improves the thermal conductivity and increases the lubricity. Use of the transfer system according to one or more of the preceding Demands on thermal transfer foils for the transfer of printing subjects to substrates (4). Use of the transfer system according to one or more of the preceding Claims for the transfer of printed images with ink-jet papers to substrates (4). Use of the transfer system according to one or more of the preceding Claims for the transfer of xerographically iron-on transfer foils Textile substrates (4).

Images