DE102021124197A1 - Process for producing a printed product - Google Patents

Abstract

A method according to the invention for producing a printed product (2), with the steps: applying (41) a high-viscosity and low-energy first fluid (10) in the planographic printing process or in the flexographic printing process; and molding (42) of a diffractive structure (11) in the first fluid using a film web (6a); is characterized by the following steps: hardening and/or drying (43) the structure (11); applying (44) a second fluid (20) to at least the region (12) of the structure; and creating (45) elevations (21) spaced apart from one another from the second fluid. The invention advantageously makes it possible to protect print-technically produced finishes from dirt and/or damage in a simple manner and with inexpensive means.

Description

invention

The invention relates to a method for producing a printed product having the features of the preamble of claim 1.

field of technology

The invention is in the technical field of the graphics industry and there in particular in the field of finishing printed products through the molding process, wherein molding is carried out using a structured film - and a fluid to be molded correspondingly structuring - and by subsequent hardening and/or drying of the molded fluid can be done.

State of the art

So-called cast-and-cure processes are known, with which, for example, holograms can be produced by printing by molding and subsequent hardening or drying.

the DE102013016117A1 discloses the creation of diffractive microstructures with an embossing cylinder. The structure is created in the fluid on the cylinder by moulding, dried and transferred to the printing material as a film.

the DE102014222677A1 discloses the creation of diffractive microstructures with an embossing cylinder. The structure in the fluid between the cylinder and the printing material wrapped around it is produced by molding and thermally dried.

Holograms are very sensitive, get dirty easily and therefore usually have to be protected, e.g. with special lacquers with a high refractive index.

So-called HRI protective coatings (HRI: high refractive index) for holograms are known. However, these are expensive and therefore unsuitable for use in industrial, inexpensively producing printing presses, in particular sheet-fed offset printing presses.

On the other hand, inexpensive UV-curable lacquers or dryable, water-based dispo lacquers as overprint protective lacquers lead to a loss of the diffractive effect of holograms due to their refractive index.

In addition, so-called drip-off processes are known in the field of printing technology finishing, in which two fluids are used, one of which drips off the other.

It's from the EP2319703B 1 a gridded drip-off method is known. The document discloses the application of a first fluid (as a screened first halftone image and preferably with anisotropy) and a second fluid (as an unscreened second image), the second fluid forming according to the screen of the first fluid by beading and pooling.

Technical task

It is an object of the present invention to create an improvement over the prior art which, in particular, makes it possible to protect print-technically produced finishes from dirt and/or damage in a simple manner and with inexpensive means.

Solution of the problem according to the invention

According to the invention, this object is achieved by a method according to claim 1 .

Advantageous and therefore preferred developments of the invention result from the dependent claims as well as from the description and the drawings.

A method according to the invention for producing a printed product, with the steps: applying a high-viscosity and low-energy first fluid in the planographic printing process or in the flexographic printing process; and molding a diffractive structure into the first fluid using a foil web; is characterized by the following steps: hardening and/or drying of the structure; applying a second fluid at least in the area of the structure; and creating spaced-apart bumps of second fluid.

Advantageous Forms and Effects of the Invention

The invention advantageously makes it possible to protect finishes produced by printing from dirt and/or damage in a simple manner and with inexpensive means.

The diffractive structures produced are advantageously protected by the elevations. For example, the structures do not clog with dirt etc. when touched with fingers.

The printed product can be a printed sheet or a printed web. the use This printing material can preferably be paper, cardboard or plastic film.

The diffractive structure can preferably be a structure with a holographic effect, e.g. a hologram.

The first fluid can preferably have a viscosity in the range from 10 Pa*s to 100 Pa*s when using offset inks or from 50 Pa*s to 500 Pa*s when using flexo inks.

The second fluid can preferably have a viscosity in the range from 50 Pa*s to 500 Pa*s, or as an index according to DIN 53211 (flow cup with a diameter of 4 mm) from 20 to 200 s.

The first fluid can preferably have a surface energy in the range from 18 mN/m to 32 mN/m and thereby form a low-energy fluid.

The second fluid can preferably have a surface energy in the range from 30 mN/m to 50 mN/m.

The two exemplary intervals given above overlap. The second fluid must have a higher surface energy value than the first fluid. So if the first fluid has e.g. 32 mN/m, the second fluid must be above it and must not be e.g. 30 mN/m.

The average distance between adjacent elevations can preferably be in the range from 50 μm to 200 μm.

The first fluid can be applied at least in regions, preferably over the entire surface. Alternatively, or at least in certain areas, the first fluid can preferably be applied in parallel strips. The stripes can preferably have a width preferably in the range from 0.25 pt to 6 pt and a distance from one another preferably in the range from 1 pt to 10 pt (1 pt corresponds to 0.3527 mm).

The film web can preferably be a plastic film web. The film web can preferably be transparent. The film web can preferably be a so-called cast-and-cure film. By using the low-energy first fluid, the film web can advantageously be detached from the first fluid without leaving any residue or at least almost without leaving any residue.

Alternatively, a rotary form could be used instead of a film web, e.g. a so-called "flexo shim". The rotary mold could be transparent and the curing and/or drying could be done from inside the rotary mold ("inside radiator").

Molding can preferably take place in the entire area of the first fluid. Alternatively, the molding can preferably only take place in regions, i.e. there are areas of the first fluid which are molded and other areas of the first fluid which are not molded.

Hardening and/or drying can preferably take place through the film web.

The application of the second fluid can preferably take place in the offset printing process or in the flexographic printing process, in particular in a coating unit.

The first fluid and the second fluid can preferably form a so-called drip-off system. The first fluid may preferably be "O555" and the second fluid may preferably be "U555". The first fluid may preferably be "O450" and the second fluid may preferably be "W450". These are product designations of the Saphira series from Heidelberger Druckmaschinen AG.

The creation of the mutually spaced elevations from the second fluid can preferably be done by dewetting. Droplets and/or beads and/or half-beads of the second fluid can preferably form during dewetting. The dewetting of the second fluid on the first fluid can be promoted by the diffractive structure of the first fluid.

The first fluid can preferably be a UV varnish. Curing can preferably take place with UV radiation. Curing can preferably take place using a UV radiator, in particular a UV LED radiator or a UV tube. The UV radiator can preferably be arranged as a so-called intermediate deck dryer. Alternatively, electron beam can be used.

The second fluid can preferably be transparent or have a translucent coloring, in particular a gloss varnish.

The second fluid can preferably be cured and/or dried, preferably after completed dewetting.

Developments of the invention

Preferred developments of the invention (in short: developments) are described below.

A development can be characterized in that the elevations are generated in such a way that the elevations are arranged on the structure and/or in gaps in the structure. The gaps can, for example, be places free of first fluid, in particular strips. The gaps can, for example, be occupied areas at which the second fluid runs off/dewetts, in particular strips.

A development can be characterized in that the elevations are generated in such a way that the elevations protrude beyond the structure. The elevations can, for example, protrude by 2 to 20 µm.

A development can be characterized in that the elevations are generated in such a way that the elevations form spacers on the printed product. The spacers can protect the diffractive structures of a printed product from being damaged by touch. The spacers can protect the diffractive structures of printed products lying on top of one another.

A development can be characterized in that the elevations are generated in such a way that the elevations are arranged to form a random pattern and/or a predetermined, non-random pattern. The pattern may preferably be a periodic pattern such as a beaded chain pattern or a checkerboard pattern.

A development can be characterized in that when the elevations are produced, the second fluid beaded on the first fluid, i.e. it formed droplets, beads or half-beads. The elevations preferably adhere to the first fluid or to the substrate (printing material, primer and/or printing inks), i.e. they are stationary on the printed product. With normal use of the printed product, they preferably do not become detached and preferably do not shift.

A further development can be characterized in that the second fluid is applied in certain areas in such a way that the second fluid forms areas of increased gloss on the printed product. Such areas can preferably coincide with areas of the first fluid which were not shaped or not structured. By choosing a suitable structure size of the structure made of the first fluid, the dripping off of the second fluid can be controlled in such a way that the second fluid is displaced completely or at least almost completely into the non-structured areas. In this way, a printed product can be produced which has diffractive areas (“positive” image) and gloss areas (complementary “negative” image).

A further development can be characterized in that a pattern and/or an image and/or a grid and/or interruptions is/are generated in the first fluid when the first fluid is applied. An optionally multicolored and optionally rastered print image can preferably lie under the first fluid.

A further development can be characterized in that a method for operating a printing press with at least six offset printing units and at least one coating unit downstream of the offset units is carried out in a first mode or in a second mode, with all six offset printing units each transferring one printing color in the first mode and varnishing unit, a varnish is transferred, the method being characterized in that a method as described above is carried out in the second mode, wherein four offset printing units each transfer one printing ink, a fifth offset printing unit downstream of the four transfers the first fluid in the offset printing process or in the flexographic printing process, in the diffractive structure is molded in a sixth offset printing unit arranged downstream of the fifth and the coating unit transfers the second fluid.

The offset printing units can be converted for the transfer of the first fluid and/or the molding, i.e. not operated as offset units.

A further development can be characterized in that the printing press is operated in a third mode, with four offset printing units each transferring a printing ink, a fifth offset printing unit downstream of the four transferring an adhesive in the offset printing process or in the flexographic printing process, and a cold foil transfer material being transferred in a sixth offset printing unit downstream of the fifth and the varnishing unit transfers a varnish.

The offset printing units can be converted for the transfer of the adhesive and/or the cold foil transfer material, i.e. they cannot be operated as offset units.

The features and combinations of features disclosed in the above sections Technical field, invention and developments as well as in the following section Working examples represent further advantageous developments of the invention - in any combination with one another.

Embodiments of the invention

the 1 until 4d show preferred exemplary embodiments of the invention and the developments. Corresponding features are in provided with the same reference numerals in the figures. Reference symbols that are repeated in the figures have been partially omitted for the sake of clarity.

1 shows a preferred embodiment of a method according to the invention. The description of the procedure also refers to the 2 B Reference or the second mode 51 shown there taken.

In the optional step 40, printing takes place, preferably using the offset printing method and preferably with at least the four colors CMYK. The printing machine 1 can be used and its four printing units 5 for printing four colors F1 to F4. At least one printed product 2 is produced or printed, with printing material 3 being printed with the various printing colors 5a, e.g. CMYK.

In step 41 the first fluid 10 is applied. In this case, a unit 5 can be used which is arranged downstream of the printing units 5 in the processing direction 4 . The application can take place using the offset printing process or using the flexographic printing process, for which purpose the work may have to be converted from an offset printing work to a flexographic printing work. The first fluid 10 can be transferred over the entire surface. However, it can also be transmitted with a pattern, an image, a grid and/or with interruptions 13 (cf. also 4a-d ).

In step 42, the diffractive structure 11, e.g. a hologram, is shaped. A foil plant 6 can be used here: a foil web 6a with a micro-structuring for molding is brought into contact with the first fluid 10 and the micro-structuring is transferred as a structure 11 into the first fluid. The foil web can be an embossing foil. Molding usually involves less pressure than classic embossing; For example, only a so-called kissprint contact can be created. At least one region 12 of the printed product 2 with a molded structure is created.

In step 43, the first fluid 11 together with its impression is cured and/or dried, preferably UV-cured. A first emitter 7 can be used here, preferably a UV emitter or a device with several UV emitters, or preferably a thermal emitter.

In step 44 the second fluid 20 is applied. A coating unit 8 can be used here. It can be applied using the offset printing process or using a flexographic printing process with a coating plate, for which the plant may have to be converted. If the drip-off process or a process with a similar effect is used to create bumps (see step 45), then the second fluid should be flowable, for which reason flexographic printing may be preferred.

The elevations 21 are produced in step 45: these can form, for example, droplets, beads or half-beads (cf. also 3a-b ). The elevation is produced by a dewetting process: the second fluid 20 dewetts or pearls on the first fluid 10 in sub-step 45a. The dewetting can be controlled: eg i) time-controlled by waiting a predetermined period of time before a subsequent step, preferably curing and/or drying; and/or eg ii) structure-controlled, in that the molded structure 11 is preferably specified in such a way (eg the pattern of the structure or its vertical and/or horizontal resolution/fineness and/or its alignment) that the dewetting is temporal and/or quantitative specified or made as required; and/or eg iii) fluid-controlled, in that the two fluids 10 and 20, preferably their surface energies, are matched to one another in such a way that the dewetting takes place in terms of time and/or quantity as specified or as required.

In optional step 46, the second fluid 20 is cured and/or dried. A second emitter 9 can be used, preferably a UV emitter or a device with several UV emitters, or preferably a thermal emitter.

2a shows a printing press 1, which is operated according to an exemplary embodiment in a first mode 50 for producing a printed product 2: several, preferably six as shown, printing units 5, e.g. offset printing units, transfer different printing inks 5a (F1 to F6) and a subsequent coating unit 8 transfers Varnish 8a (L) on the printing material 3. The work 6 can be designed as a foil work, which is not used as such in the first mode 50, but for printing color.

2 B shows a printing press 1, which is operated according to an exemplary embodiment in a second mode 51 for producing a printed product 2: several, preferably four as shown, printing units 5, e.g. offset printing units, transfer different printing colors 5a (F1 to F4), a subsequent unit 5 serves the application 41 of the first fluid 10, a subsequent film unit 6 with a film web 6a is used for molding 42 the diffractive structure 11 in the first fluid 10 and a subsequent coating unit 8 is used for the application 44 of the second fluid 20 on the printing material 3; two radiators serve to harden and/or dry the two fluids 10 and 20.

2c shows a printing press 1, which is operated according to an exemplary embodiment in a third mode 52 for producing a printed product 2: several, preferably four as shown, printing units 5, e.g. offset printing units, transfer different printing colors 5a (F1 to F4), a subsequent unit 5 transfers Glue 5b (K), a subsequent foil unit 6 transfers foil transfer material 6b (KF; e.g. cold foil transfer material), and a subsequent coating unit 8 transfers coating 8a (L) onto the printing material 3.

The in the 2a-c The printing press 1 shown in each case can be the same printing press, ie the same printing press 1 is optionally operated in one of the different modes 50, 51 and 52. The printing press can be converted for this purpose, eg by changing the colours/adhesive/varnish and/or by changing the foils (transfer foil and impression foil).

3a shows a preferred embodiment of a printed product 2 produced according to the invention in a sectional view. There is a (cured and/or dried) layer of first fluid 10 on the printing material 3, possibly with a pattern/image/raster/interruptions. The diffractive structure 11 produced by molding can be seen in the layer. (Hardened and/or dried) elevations 21, for example droplets or beads, of dewetted second fluid 20 sit on the layer. Printing ink 5a (one or more colors, for example CMYK) is optionally located on the printing material 3. The elevations 21 have an average distance 22 from one another. The elevations 21 have an average height 23 and an average overhang 23a (above the layer of first fluid 10). Due to the overhang, the elevations 21 form so-called spacers 24 and protect the diffractive structure 11.

3b shows another preferred embodiment of a printed product 2 produced according to the invention in a sectional view. On the printing material 3 there is a (hardened and/or dried) interrupted layer of first fluid 10, possibly with a pattern/image/grid. The layer has gaps 14. The diffractive structure 11 produced by molding can be seen in the layer. In the gaps 14 of the layer sit (hardened and/or dried) elevations 21, for example droplets or pearls, of dewetted second fluid 20. Printing ink 5a (one or more colors, for example CMYK) is optionally located on the printing material 3. The elevations 21 have an average distance 22 from one another. The elevations 21 have an average height 23 and an average overhang 23a (above the layer of first fluid 10). Due to the overhang, the elevations 21 form so-called spacers 24 and protect the diffractive structure 11.

4a shows a further preferred embodiment of a printed product 2 produced according to the invention in plan view. The first fluid 10 or the diffractive structure 11 formed therein is located on the printing material 3. The second fluid 20 or the elevations 21 (spacers 24) consisting of it form a random pattern 25. The random pattern is formed during the dewetting process. The second fluid is on top of the first fluid and/or in its gaps if, for example, "negative" lines were printed with the first fluid (the gaps would be the "positive" lines).

4b shows a further preferred embodiment of a printed product 2 produced according to the invention in plan view. On the printing material 3 there is a first fluid 10 or the diffractive structure 11 molded therein line pattern or a pearl necklace pattern. The predetermined pattern is formed during the dewetting process, it being possible for the pattern to be predetermined or controlled, for example, by the diffractive structure 11 and/or its gaps 14 . The second fluid is on the first fluid and/or in its gaps.

4c shows a further preferred embodiment of a printed product 2 produced according to the invention in plan view. In this embodiment, both a random pattern 25 and a predetermined pattern 26 with stripes 31 can be seen: in this respect, the same applies to the 4a and 4b described.

4d shows a further preferred embodiment of a printed product 2 produced according to the invention in plan view. The printed product has a region 30 without an impression or without a diffractive structure 11 . This area forms an area 32 of increased gloss. Otherwise, this applies to the random pattern 25 shown or to a predetermined pattern that is not shown 4a (respectively. 4b) described.

Reference List

1

printing press

2

print product

3

substrate

4

processing direction

5

Works/printing units/offset printing units

5a

ink

5b

Glue

6

foil work

6a

film web

6b

foil transfer material

7

First Radiator

8th

coating unit

8a

paint

9

Second Radiator

10

First fluid

11

Diffractive structure/hologram

12

Area with impression/structure

13

Pattern/Image/Grid/Breaks

14

gaps in the structure

20

second fluid

21

Bumps/droplets/pearls/half-pearls

22

Medium distance

23

medium height

23a

Medium overhang

24

spacers

25

random pattern

26

Default pattern

30

Area without impression/structure

31

stripes

32

Area of increased gloss

40

Print

41

Application of first fluid

42

molding structure

43

hardening/drying

44

Apply second fluid

45

Generate surveys

45a

Beading/Dewetting

46

hardening/drying

50

First mode

51

second mode

52

Third mode

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102013016117 A1 [0004]
• DE 102014222677 A1 [0005]
• EP 2319703 B [0010]

Claims (10)

Method for producing a printed product (2), with the steps: - applying (41) a high-viscosity and low-energy first fluid (10) in the planographic printing process or in the flexographic printing process; and - molding (42) of a diffractive structure (11) in the first fluid using a film web (6a); characterized by the steps of: - curing and/or drying (43) the structure (11); - applying (44) a second fluid (20) at least in the area (12) of the structure; and - producing (45) elevations (21) spaced apart from one another from the second fluid. procedure after claim 1 , characterized in that the elevations (21) are produced in such a way that the elevations are arranged on the structure (11) and/or in gaps (14) in the structure. Method according to one of the preceding claims, characterized in that the elevations (21) are produced in such a way that the elevations protrude beyond the structure (11). Method according to one of the preceding claims, characterized in that the elevations (21) are produced in such a way that the elevations form spacers (24) on the printed product (2). Method according to one of the preceding claims, characterized in that the elevations (21) are generated in such a way that the elevations are arranged to form a random pattern (25) and/or a predetermined, non-random pattern (26). Method according to one of the preceding claims, characterized in that when the elevations (21) are produced (45), the second fluid (20) bubbles (45a) on the first fluid (10). Method according to one of the preceding claims, characterized in that the application (44) of the second fluid (20) takes place in regions such that the second fluid forms regions (32) of increased gloss on the printed product (2). procedure after claim 1 , characterized in that when applying (41) the first fluid (10) a pattern and/or an image and/or a grid and/or interruptions (13) is or are generated in the first fluid. Method for operating a printing press (1) with at least six offset printing units (5) and at least one coating unit (8) arranged downstream of the offset units in a first mode (50) or in a second mode (51), with each six offset printing units having one in the first mode Printing ink (5a) is transferred and a varnish (8a) is transferred in the coating unit, characterized in that in the second mode (51) a method according to one of the preceding claims is carried out, with four offset printing units (5) each transferring one printing color (5a), a fifth offset printing unit (5) downstream of the four transfers the first fluid (10) in the offset printing process or in the flexographic printing process, the diffractive structure (11) is molded in a sixth offset printing unit (5, 6) downstream of the fifth and the coating unit (8) transfers the second Fluid (20) transmits. procedure after claim 9 , characterized in that the printing machine (1) is operated in a third mode (52), with four offset printing units (5) each transferring a printing ink (5a), a fifth offset printing unit (5) downstream of the four transferring an adhesive (5b) in the offset printing process or in a flexographic printing process, a cold foil transfer material (6b) is transferred in a sixth offset printing unit (5, 6) downstream of the fifth and the coating unit (8) transfers a coating (8a).

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