DE102006012329A1 - Ink, useful for printing in flexographic- or offset printing process, comprises expandable elements for volume expansion under the effect of heat and organic and/or inorganic infrared absorber - Google Patents

Abstract

Ink, for printing in flexographic- or offset printing process, comprises expandable elements for volume expansion under the effect of heat; and organic and/or inorganic infrared absorber, which improves the heat transmission into the ink when exposed to infrared radiation. Independent claims are included for: (1) a print product comprising a first sub-image that is at least partly printed by offset printing and a second sub-image that is printed by offset printing and/or flexographic printing, and then possibly surface-coated, where the second sub-image is printed with one or more printing inks or coatings containing elements that are expandable under the effect of heat and the first and the second sub-images are produced on the printing substrate in a single printing step by means of a printing machine; (2) the production of the print product comprising printing the second sub-image on the printing substrate by an offset printing unit containing an offset printing dye with expandable elements and which is present in a sheet-fed offset printing machine; (3) a heat input device, for implementing the print product production, comprising one or more infrared emitters; and (4) a printing machine for the production of a print product comprising a sheet rotary printing machine.

Description

The Invention relates to a printing ink, a printed product, a process, a device and a printing press according to the preambles of claims 1 to 3, 10, 11, 12, 15, 16, 20, 21, 23, 27 and 32.

It is known from the prior art printing inks containing a blowing agent and foam under heat to print. The DE 25 29 043 C2 describes a process that has also become known under the heading "Kiwoprint." In this process, a very high layer (eg 200 .mu.m) is applied to a printing material containing a pore-forming agent by means of the screen-printing process.This layer is then pressurized to 185.degree For 10 minutes, the printed surface is gelled and, thanks to the pore-forming agent, foamed to about three times as high a layer thickness (eg 500 to 700 .mu.m.) The disadvantage of this method lies in the required long heat exposure time in order to achieve the desired effect It is obvious that this method is suitable for one-off production or production of smallest editions, but not for modern printing processes with a throughput rate on a printing machine up to 18,000 sheets / h The selected printing process, the screen printing, combined with the high required layer thicknesses, includes one industrial production, since the layer thicknesses before storage after de m pressure must be dried or stored individually in suitable drying devices.

Methods have become known in which a thermo-expansive printing substrate is partially coated with an absorber material which absorbs the heat radiation and expands the thermo-expansive printing material at the printed areas and thus forms a relief. The US 5 122 430 A describes a method in which a thermo-expansive printing material is applied to a high-density ink with, for example, aluminum or metal components. When exposed to a heat radiator, the paint releases the absorbed heat to the substrate, causing the substrate to expand. The metallic components ensure that the incident IR radiation is better absorbed.

The US 5 650 217 A describes an identical process wherein the absorbing ink does not contain any metallic constituents, but is a high density or, ideally, black color. A comparable process describes the US 5639540 , wherein the absorbent high-density or black color is applied by means of a ribbon on the ground. The disadvantage of this method is that the user is bound to specific, thermo-expansive substrates. Classic and well-established substrates, such as paper and cardboard, can not be used for this process. In addition, the inclusion of non-transparent absorbers in the ink, such as metal particles or black pigments, limits the user in the design of the print engine, since these printed areas and elements are clearly visually recognizable and therefore included in the design of the print product Need to become.

The EP 0 340 898 B1 describes a security coding for an article wherein a colorless or slightly colored material with a significant absorption in the near infrared region is applied. The material containing the infrared absorber may also be an ink. The addition of an infrared absorber in a printing ink is therefore previously known. The aim of the invention is, inter alia, to encode a printed product in the sense of protection against counterfeiting by absorbing a suitable laser beam at specific points of the product.

The EP 1 302 735 A1 suggests using radiant energy to dry inks and varnishes which emit at a wavelength that is substantially unabsorbed by water. This is to avoid that substrates under the action of radiation dehydrate and become brittle. In order to improve the coupling of the radiation energy into the printing ink or varnish, it is proposed to add to the printing ink or varnish an infrared absorber which absorbs in the near infrared.

The DE 10 2004 011 347 A1 describes another group of infrared absorbers attached to printing inks and varnishes. The aim of both patents is to improve the drying of printing inks. Add ink and varnish infrared absorber, is therefore previously known. These were previously used exclusively in printing inks to improve the drying of these paints or varnishes.

It is known to add plastics to infrared absorbers. In the DE 100 22 037 A1 For example, a thermoplastic resin is disclosed to which infrared absorber has been added. Plastics are added to infrared absorbers, for example, to reduce the thermal conductivity of plastic discs. Another known application of infrared absorbers in plastics is to improve the weldability of plastics with NIR lasers. Both known applications have no connection with the field of the invention, the printing ink technology and the printing technique.

As intumescent substances in printing inks microspheres are known. Microspheres are small Plastic balls consisting of a polymer capsule in which a gas is trapped. As this gas is heated, the pressure increases and the thermoplastic shell softens. This increases the volume of the microspheres by 40 times. Unexpanded microspheres can be used as blowing agents in printing inks, paper and technical textiles and plastics.

Printed images, which was printed with a printing ink with microspheres can, under the effect of heat expand and form a relief. As a result, so-called pseudo-impressions can be achieved, which find use in the design of printed matter, as well in the training of braille and pictures. Preserved printed areas by the expansion also a velvety, soft surface. One tactile effect, which also likes to set in the packaging becomes. The disadvantage of the hitherto known printing inks, however, is that the printed area must be heated to at least 75 ° Celsius to the full To achieve expansion. Such a high heating is with the known Devices for heating of the printing sheet in printing presses, such as infrared radiators and hot-air swords, while of the print run can only be achieved if the print speed is drastically reduced reduced and the acting heat output maximum chosen becomes. This high heat input has but definitely negative consequences for the printed product: The paper or cardboard may dry out and also other printed areas can become sticky and in the worst case lay down or on machine elements Lubricate. It is also known sheets of paper with a printing ink were printed, the microspheres included, after printing by the printing press a separate touching Supply heating device, the the inflatable Ink film heats up. However, such an approach is not especially economical, because you have to invest in a separate heater. Here too becomes a relatively long time for heating the ink layer with microspheres needed so that the throughput of such a device is limited.

The Expansion speed of the ink layer with the integrated Microspheres also depend very dependent on which pigments the printing ink or varnish colored is. Black or blue colored Printing ink expands faster with the same power effect as transparent or light shades. This phenomenon can be explained attributed that blue or black pigments absorb the IR rays better and the heat be forwarded to the embedded in the ink microspheres. The design possibility However, a printed product is significantly limited if the effect of expansion economical only with dark colors works. The observed effect, however, shows that by a improved absorption of the IR rays in the ink film the Expansion significantly accelerated.

task It is therefore an object of the present invention to provide a method in the pseudo-imprints and other changes the tactile surface from sheet in economic Way solved become.

Is solved this task in a printing ink, a printed product, a process, a device and a printing press according to the features of claims 1 to 3, 10, 11, 12, 15, 16, 20, 21, 23, 27 and 32.

further developments The invention will become apparent from the respective dependent claims.

The Invention is that a method is used in which, by even printing of a printing ink under heat intumescent Substances and optionally organic or inorganic IR absorbers contains on a substrate, the printed with this ink Bow afterwards fed to an IR radiation source is and by the induced in the ink and by the IR absorber absorbed IR radiation by heat input the inflatable ones Substances that inflates Ink layer is changed in their tactile properties.

A change the tactile properties in the sense of the invention can be a noticeable relief formation, a velvety surface or a matte effect. Furthermore, the invention describes Devices for carrying out of such a method and particular embodiments of swellable substances.

In In a first embodiment of the invention, the expansion of Improved ink layers with microspheres embedded therein, in which the printing ink or the paint is preferably transparent or only slightly colored organic or inorganic infrared absorbers are added to the coupling of the heat radiation to improve in the ink film.

The organic infrared absorbers may be those in the EP 1 302 735 A1 proposed cyanine dyes or the in the DE 10 2004 011 347 A1 for printing inks proposed infrared absorber group of cyanines, naphthalocyanines, squaraine and croconates or other known organic infrared absorbers.

There are also mixtures of different infrared absorbers in the ink conceivable. The IR absorber should have no or only a slight absorption in the visible range to a color impairment of the printing inks or the paint film to avoid. Of course, the IR absorber can absorb more in the visible spectral range, if the color strength and hue allow this. For the purposes of the invention, therefore, all known organic infrared absorbers are permissible as long as the color impression of the ink film is not significantly affected by the addition of the infrared absorber.

In contrast to the technology EP 1 302 735 A1 and DE 10 2004 011 347 A1 The infrared absorbers are added in the ink, not primarily to achieve the drying of the ink, but to achieve a faster and thus more economical expansion of the microspheres in the ink.

alternative or in addition to organic infrared absorbers, the printing ink can also inorganic infrared absorber are attached. A well-known, largely transparent inorganic infrared absorber is exemplified by iridium tin oxide (ITO), which can absorb infrared radiation very well.

The However, the invention also includes all other known inorganic Infrared absorbers, if the condition is met is that for a given ink of a hue with a certain color strength in color by the addition of the inorganic infrared absorber not essential and disturbing being affected. As the color impression of an expanded Ink surface change can (for example, from transparent to white), this condition of the not falsified Color impression in the first place for apply the expanded state.

In a second embodiment the printing ink called microspheres, which is a polymeric capsule comprising a gas and coated with a coating containing infrared absorber. Thereby becomes a microsphere itself to an infrared absorber element and the heat radiation will be at the microsphere directly and largely lossless converted into heat. Especially in mineral oil colors is the heat conduction not ideal, allowing the direct coupling of the infrared rays at the microspheres brings significant advantages in the expansion speed.

In In a third aspect of the invention, the polymer containing the capsule the microsphere forms, itself an organic or inorganic infrared absorber. The Admixture of infrared absorbers in plastics is from the thermal insulation and the Plastic Welding Technology well known. Due to the fact that the polymer of the microsphere has a Contains infrared absorber, will also be through this solution the infrared radiation is absorbed directly at the microsphere and largely lossless in heat implemented. Also this solution increases the speed of expansion in an advantageous manner.

Of Furthermore, the invention comprises a printed product and devices for producing such a printed product.

The Printed product is characterized by the fact that at least parts printed in the offset printing process, the used Printing ink is not inflatable Contains elements and another part of the print image printed with a printing ink become, the inflatable Contains elements. These inks with expandable Elements can be over Offset inking unit or over a coating unit or flexo printing unit are to be printed. characteristic for the Printed product is that the printed product, partially with printing inks intumescent Elements and partially printed with inks that are not inflatable elements contains arises in a printing pass in the passage through a printing press. The volume change of the partial image that was printed with the inks with inflatable elements, can be due to the heat a suitable device, for example one or more infrared emitters, one or more hot air blowing devices, by microwave radiation and / or by contact with a heated one Cylinder or roller during the printing run are inflated by the printing press. The effect can be provided zonally aligned.

alternative the print image can also be outside the press are inflated by a separate device, those with devices for heat Is provided. This offline attachment can work with the same devices be equipped as they are in-line during the process Print run used by the printing press. This offline attachment outside the printing press can be a separate device, exclusively the the effect of heat serves for Relienstzeugung. This offline systems are conceivable, the Whole sheet or partial sheet or use after cutting or punching process a printed product. As an alternative, the or can the devices for heat treatment the printed product according to the invention also part of a cutting device, a punch, a gluing machine or a carton erecting machine, as is conventional be used in postpress after finishing.

A particular embodiment of the printed product according to the invention is that first the ink or varnish layer is applied, which contain the intumescent elements and then this layer with at least one con conventional printing ink and / or lacquer layer is overprinted. In this case, the bulking of the intumescent elements, which are contained in the preprinted printing ink or lacquer layers, can take place before the subsequent overprinting with at least one conventional printing ink and / or at least one lacquer layer with a suitable device for effecting heat, or the printed product is completely printed and optionally painted and then the expandable elements are expanded by the action of a suitable device for the action of heat. Conventional printing inks for the purposes of the invention are printing inks that contain no expandable elements, that is, they include offset inks that dry oxidatively and / or by whipping, water-based paints, but also printing inks and coatings that cure by radiation curing. This type of design allows a velvety surface with a high matte value. In the subsequent overprinting can be achieved by overprinting the parts of the print image with an ink or varnish layer containing intumescent elements, with parts of the print image very good matte / gloss effects. Such matt / gloss effects are often used for the decorative design of the printed products. The method disclosed here enables a matte / glossy effect to be achieved without the makeready effort of the press. It is also characterized by a good register to the other parts of the printed image. The matte effect can be increased even further by adding silicones or silicone oil in small proportions to the ink with the intumescent elements. This process for achieving matt / gloss effects is also very easy to represent economically, since intumescent elements, such as microspheres, are produced in large quantities and thus are available at low cost.

The The invention also describes a printing machine for the production of printing products according to the invention, wherein the printing press comprises at least one offset printing unit. In the case that the inflatable Printing layers are inflated in the printing press by the action of heat are intended, the printing press also includes devices for heat input in the printed product. This can Infrared radiator, hot air swords or heated rollers or cylinders that are in direct contact stand with the substrate. The rollers or cylinders can be direct be heated by flowing through a heating fluid or include an electric heater. You can also indirectly through a Irradiation by a heat radiator Working temperature to be brought.

Claims (34)

Printing ink for printing in flexo or offset printing with inflatable elements contained therein for volume expansion under the influence of heat, characterized in that the printing ink additionally organic and / or inorganic infrared absorber containing the heat input into the ink when exposed to infrared radiation improve. Printing ink for printing in flexo or offset printing with inflatable elements contained therein for volume expansion under the influence of heat, being the inflatable Elements microspheres are, consisting of a polymer shell as capsule material, the a heat expandable Gas surrounds, characterized in that the polymer shell itself as capsule material contains organic and / or inorganic infrared absorber. Printing ink for printing in flexo or offset printing with inflatable elements contained therein for volume expansion under the influence of heat, being the inflatable Elements microspheres are, consisting of a polymer shell as capsule material, the a heat expandable Gas surrounds, characterized in that the polymer shell with an additional Coating or coating is provided, the organic and / or inorganic infrared absorber contains or the coating itself absorbed in the infrared spectral range. Printing ink according to claim 1, 2 or 3, characterized in that in the ink or in the ink located inflatable baren element contained infrared absorber in their spectral absorption characteristics be selected in the visible spectral range so that they are the color Impression of the bloated Ink layer not or only to a very small extent distort. Printing ink according to claim 1, 2 or 3, characterized in that in the ink or in the ink located swellable element contained infrared absorber preferably in the near infrared (0.7 up to 1.4 μm) absorb the IR radiation. Printing ink according to claim 1, 2 or 3, characterized in that in the ink or in the ink located swellable element contained infrared absorber, preferably in the short-wave infrared (1.4 to 3 μm) absorb the IR radiation. Printing ink according to claim 1, 2 or 3, characterized in that in the ink or in the ink located swellable element contained infrared absorber preferably in the medium wave infrared (3 to 8 μm) absorb the IR radiation. Printing ink according to claim 1, 2 or 3, characterized in that in the ink or in the ink located swellable element contained infrared absorber preferably in the long-wave infrared (8 to 15 μm) absorb the IR radiation. Printing ink according to claim 1, 2 or 3, characterized in that in the ink or in the ink located inflatable baren element contained infrared absorber or infrared absorber mixtures over several Absorb spectral regions in the infrared wavelength range. Printed product consisting of a first partial image, that at least partially printed in offset printing and a second Partial image that is printed in offset and / or flexo and subsequently optionally painted, characterized in that the second Partial image with one or more inks or paints under action of heat intumescent Elements included, printed and the first and the second field generated in a printing pass on the printing substrate by a printing press becomes. Process for producing a printed product according to Claim 10, characterized in that the second partial image by an offset printing unit containing an offset printing ink with expandable elements in one Sheet-fed offset printing machine is printed on the printing substrate. Process for the preparation of a printed product according to Claim 10, characterized in that the second partial image by a flexo or coating unit that uses a flexo ink or varnish with inflatable Contains elements is printed on the printing substrate in a sheet-fed printing press. Process for the preparation of a printed product according to Claim 11 or 12, characterized in that the printing ink or the paint with the inflatable ones Elements contains no infrared absorber. Process for the preparation of a printed product according to Claim 11 or 12, characterized in that at least one Printing ink according to claim 1, 2 or 3 for the generation of the partial image with the inflatable printing inks used becomes. Process for the preparation of a printed product according to Claim 10, characterized in that the intumescent layers during the Print run through the press in an inline process a suitable device can be expanded by heat input. Process for the preparation of a printed product according to Claim 10, characterized in that the printed product within the printing press is completely finished and the still flat expandable layers of the second sub-image in a downstream of the printing press separate device in an off-line process by heat input to be expanded. Process for the preparation of a printed product according to Claim 15 or 16, characterized in that the heat input for the expansion of the inflatable Layers of the second partial image by a suitable device done on a whole sheet. Process for the preparation of a printed product according to Claim 15 or 16, characterized in that the heat input for the expansion of the inflatable Layers of the second partial image by a suitable device on a partial sheet or benefits. Process for the preparation of a printed product according to Claim 15 or 16, characterized in that it is in the intumescent Ink layers around in UV light or by means of an electron beam curable Ink layers and this after blowing Additionally cured by a UV or electron beam curing device, that of the device for the heat input is subordinate. Method for producing a matt / gloss effect on a printed product according to claim 10, characterized in that that the entire print product is painted flat with a gloss varnish and then the expansion of the inflatable ink layers by heat input takes place, and thus the paint layer over the part of the image, which with the inflatable Printing inks is frosted, while the paint layer over the other parts of the printed product remains shiny. Method for producing a matt / gloss effect on a printed product according to claim 10, characterized in that that the entire printed product is flat is painted and before the painting process, the expansion of the inflatable ink layers by heat input takes place, and thus the paint layer over the part of the image, which with the inflatable Printing inks is frosted, while the paint layer over the other parts of the printed product remains shiny. A method according to claim 20 or 21, characterized in that for the generation of the sub-image, which later expands to produce the matte effect is going to be used, inks next to the inflatable elements Silicones or silicone oils for reinforcement of the matte effect. Device for the heat input to carry out A method according to any one of claims 11 to 22 in that it is one or more infrared radiators. Device for the heat input to carry out A method according to any one of claims 11 to 22 in that it is one or more infrared laser sources which is preferably as a semiconductor laser or Nd-Yag laser or CO2 lasers are formed. Device for the heat input to carry out A method according to any one of claims 11 to 22 in that it is one or more thermal air sources such as fan heaters or thermal air swords. Device for the heat input to carry out A method according to any one of claims 11 to 22 in that it is a roller, a cylinder or a cylinder Plate acts during the heat transfer in contact with the printed product, and the roller, the cylinder or the plate directly, for example via an electric heater, or indirectly a heat radiator are heated. Device for the heat input to carry out A method according to claim 16, characterized in that the device is integrated in a sheet punch. Device for the heat input to carry out A method according to claim 16, characterized in that the device is integrated in a cutting machine. Device for the heat input to carry out A method according to claim 16, characterized in that the device is integrated in a folding machine. Device for the heat input to carry out A method according to claim 16, characterized in that the device is integrated in a collating machine. Device for the heat input to carry out A method according to claim 16, characterized in that the device is integrated in a folding box gluing machine. Printing machine for producing a printed product according to claim 10 or for carrying out a A method according to claim 15, 16 or 20, characterized by that it is a sheet-fed rotary printing press. Printing machine according to claim 32, characterized in that that it is a sheet-fed rotary printing press with double-sized printing cylinders and grab transport. Printing machine according to claim 32, characterized in that that the sheet-fed rotary printing machine devices for heat input in the inflatable Contains ink layers, that make it possible these to each of the specific operating temperature, preferably between 60 and 150 degrees Celsius, too heat.