EP0826823A1 - Special paper - Google Patents

Abstract

Special printable paper, with a coating on at least one side containing film-forming organic pigments (A) and binders (B). Also claimed is (i) a process for the production of this paper by coating or impregnating a paper substrate on at least one side with a mixture containing (A) and (B); (ii) printed special paper with a layer on at least one side containing printing ink embedded in a mixture of (A) and (B) in the form of a film or sintered together; (iii) a process for the production of this printed paper by printing on the coated paper and then forming a film by heating; (iv) a printing system, especially an ink jet printer, with an integrated heating and optionally pressure-producing system for film-forming, preferably heated rollers.

Description

TECHNICAL AREA

The present invention relates to a printable as well as a special printed paper, process for their production, uses thereof and a device for producing the printed Special paper.

STATE OF THE ART

Special papers are used especially in the field of inkjet printing used with an inorganic pigment Coating provided among other things to increase the brilliance are. The materials used for the coating are for Partly expensive, which is not negligible on the price of inkjet paper affects. Accordingly, the coating is tried run as thin as possible. Show despite the coating water-based inkjet prints only low wipe and / or water resistance on. Their lightfastness also leaves something to be desired left.

To protect inkjet prints, especially against moisture and blurring, and to some extent also to increase the Brilliance, these are often laminated with a film, for what special laminators are available. Such applications can also be found in the ID or security area, with additional often a photo, passport photo or the like in the film with "welded in". This welding in represents skillful counterfeiters is hardly an obstacle to counterfeiting.

PRESENTATION OF THE INVENTION

The object of the invention is to specify how, in particular, inkjet prints, more abrasion-resistant, smudge-proof, water-resistant, brilliant, more lightfast and finally even more stable in Can be made for increased security against counterfeiting.

In view of this task, the subject of the invention printable special paper according to claim 1 and a method for the production of such paper according to claim 4.

The invention further relates to a printed special paper according to claim 9 and a method for producing such Special paper according to claim 11.

Claims 20-22 relate to special uses of the inventive Special papers.

Finally, the subject of the invention is a printing device according to claim 23.

The essence of the present invention is therefore based on Paper or a paper substrate has a film-forming, organic pigments (plastic pigments) and binders apply coating and apply this after Printing by application of at least heat, preferably but of heat and pressure to film it. The printing ink will here between the melting or sintering together Plastic pigments embedded and can be no longer blur. The paper surface becomes abrasion-resistant due to the plastic film, film-like properties and is at least water-repellent, if not sealed waterproof. The printed image appears with the viewer increased brilliance. It has also been shown that according to the invention printed images produced much more lightfast are as conventional inkjet prints. Additional and expensive laminations, as they are common with inkjet papers, will not needed and can be omitted.

In terms of apparatus, it is no more than a a suitable heat source such as a hot air blower or a heat radiation lamp. However, as mentioned, it is preferred exerted pressure at the same time. It can be done very easily a common, commercially available, e.g. in a continuous process Laminator with heated pairs of rolls or rolls take place as it is for the aforementioned lamination of film a paper substrate is commonly used. Of course other, heated presses or the like can also be used will. The one needed for the filming could be advantageous Device also integrated directly into a printer and there Requires automatically after the actual printing process be used.

By embedding the printing ink in the developing Plastic films are subsequent changes to the printed image, without this being recognizable, hardly possible anymore. The invention is therefore particularly suitable for use in the security area such as. for the production of ID cards, passports, certificates or similar.

Water resistance and smudge resistance, but above all high Brilliance are typical characteristics of photographic prints Photos. With the invention e.g. starting from electronically stored images "paper prints" of practical same quality from everyone with a standard inkjet color printer and make a simple laminator. Compared The coated special paper for photo paper is according to the Invention much cheaper. Even the surface quality The images in the sense of "matt" or "glossy" can be in the simplest Be controlled and determined by choice of ways Surface, which during filming with the image surface is in contact under pressure. So it is sufficient, for example, together with the image or print to be filmed a matt or glossy film to pass through a continuous laminator. For "matt" surfaces are foils with a roughness depth between Suitable for 0.01 - 5 µm and for "shiny" ones with a roughness depth less than 0.01. µm. The film must be after filming of course, peel it off well from the filmed surface to let. Polyester or polyamide films are therefore suitable (such as GRILON 6, 10, 12). For rolls of continuous devices for filming or printing plates from flat presses Teflon or chemical materials for good Be removable.

• 20-90% organische Pigmente,
• 1-30% Bindemittel
• 0-20% anorganische Pigmente
• 0- 1% tenside Netzmittel
• 0- 5% UV-Stabilisatoren
• 0- 3% Hydrophobierungs-/Leimungsmittelmittel
• 0-10% Weichmacher.

The coating of the special paper according to the invention preferably has the following composition:

• 20-90% organic pigments,
• 1-30% binder
• 0-20% inorganic pigments
• 0- 1% surfactant wetting agent
• 0- 5% UV stabilizers
• 0- 3% water repellent / sizing agent
• 0-10% plasticizer.

The percentages given above are based on the dry condition the coating on the finished paper.

Organic pigments include Styrenes, acrylates or combinations of which with melting points in the range between 90-180 ° C, but especially between 110-140 ° C in question and as Binder starch, polyvinyl alcohol, polyvinyl pyrolidone or a plastic dispersion containing acrylate, styrene or PVAC.

The inorganic pigments are optional, but can be increased the brilliance may be added. Silicas are suitable, Aluminum oxyhydrates, kaolins or carbonates.

The UV stabilizers are also optional, especially since print images produced according to the invention are already very lightfast have proven.

With the surfactant wetting agents and / or the waterproofing or Sizing agents can primarily affect wetting or penetration behavior the coating composition on or controlled in the paper substrate if this proves to be necessary.

To achieve the desired effect, the coating should be applied with a dry weight of 5-15 g / m ² .

There are no special requirements with regard to the type of paper substrate and its basis weight. Normal cellulose or cotton papers or combinations thereof with typical basis weights in the range between 80 g / m ² and 300 g / m ² are suitable. For "paper prints" of photos you will prefer to use papers with a higher basis weight in the upper part of the specified range. The structure is the same for applications in the security area, but papers with additional security elements (such as watermarks, chemical security agents or paint applications containing iridescent pigments) in the weight range of 70-150 g / m ² are preferably used here. For most applications it should be advantageous if the coating partially or even completely penetrates the paper and actually impregnates it.

It is advantageous to use the mixture to make the coating in the form of a dispersion, preferably an aqueous dispersion, to spread. The mixture can be applied "Offline" on the finished, dry paper substrate or already "Inline" in the paper machine on the still unfinished paper web respectively. In any case, the subsequent drying should be at a Temperature are carried out at which no film formation occurs, preferably at a temperature of at most 70 ° C.

The organic pigments are preferably selected or put together that filming at a temperature range between 90-180 ° C, but especially between 110-140 ° C can be executed. These temperatures can be with conventional Easily reach laminators. At lower temperatures there would be a risk that the filming would be premature, especially during the coating drying process or the paper web or during transport or storage of the finished paper occurs. At temperatures higher than those specified there is a risk that the paper will dry out too much becomes what's on its properties and flatness could have an adverse effect.

As mentioned, preference is given to filming other than heat pressure applied simultaneously. A pressure in the range between 0.5-5 bar in a static press or a corresponding line pressure in a continuous laminator has proven to be sufficient and proven cheap.

The application of the invention is not to prints with inkjet inks limited, although here the advantages according to the invention especially come into play. Laser printing can also be done film very well.

EXAMPLES example 1 Coating color

A mixture of 70% by weight plastic pigment DPP 722 E from the Dow Europe S.A., CH-8810 Horgen (organic pigment), 22 % By weight of ROPAQUE OP-84 from Christ Chemie AG, CH-4147 Aesch (organic pigment), 4% by weight polyvinyl alcohol (Binder) and 4% by weight of EGRAN HP from Bearle CH-4142 Münchenstein / Basel (water repellent) is added with water worked up a dispersion that can be applied as a "coating color". The water content in the dispersion is adjusted to 70% by weight.

The plastic pigment DPP 722 E from Dow Europe S.A. is as Suspension available. The individual pigment grains are full spheres. For the filming, a temperature is in the range between 120 ° C and 140 ° C required. ROPAQUE OP-84 is also a suspension. The individual pigment grains are hollow bodies. For the filming is a temperature in the range between 80 ° C. and 110 ° C required. The 3: 1 mixture of both components can be used at a temperature in the range between 110 ° C and Film at 120 ° C.

Example 2 Printable special paper for normal inkjet applications

On a finished, dry paper web made of cellulose paper with a basis weight of 100 g / m2, the coating color according to Example 1 with a layer thickness of 10 g / m ² (dry weight) is applied evenly on one side in a coating machine and subsequently in a (possibly extended) drying section dried at 70 ° C.

Example 3 Printable special paper for normal inkjet applications

In a paper machine, the coating color according to Example 1 with a layer thickness of 10 g / m ² (dry weight) is applied evenly on one side to the paper web with a later basis weight of 100 g / m ² before the end of the drying stage and the web thus coated is subsequently applied in one (if necessary extended) drying section dried at 70 ° C.

Example 4 Printed special paper

A sheet of a printable produced according to Example 2 or 3 Special paper is printed using an inkjet printer. After the ink has dried, the sheet is allowed to Filming the coating through a continuous laminator, which is set to a temperature of 140 ° C.

Example 5 Security document / ID

A sheet of special printable paper produced analogously to Example 2 or 3 but with a basis weight of 100 g / m ² and a coating on both sides with the coating color according to Example 1 of 10 g / m ² is printed with an inkjet printer, with the exception of text and Ornaments an image, for example a passport photo of a person, which was previously transferred by scanning in electronic form or directly recorded with a digital camera, is also printed on. After the printing ink has dried, the sheet is passed through a continuous laminator to film the double-sided coating, which is set to a temperature of 140 ° C. It is possible to additionally authenticate the document before filming, by means of a hand-applied signature.

Example 6 Prints of photographs

A sheet of a printable special paper produced according to Example 2 or 3, however, with a basis weight of 200 g / m ² and a coating on its front side with the coating color according to Example 1 of 14 g / m ² and a coating on its back with 3 g / m ² stearate pigments printed on the front with an inkjet printer with an image motif, which was previously transferred into electronic form by scanning or directly recorded in this form with a digital camera. After the printing ink has dried, the sheet is passed through a continuous laminator, which is set at a temperature of 140 ° C., to film the coating.

Claims (24)

Printable special paper, characterized by a film-forming organic pigments applied at least on one side and coating containing binders. Special paper according to claim 1, characterized in that the coating has the following composition: 20-90% organic pigments, 1-30% binder 0-20% inorganic pigments 0- 1% surfactant wetting agent 0- 5% UV stabilizers 0- 3% water repellent / sizing agent 0-10% plasticizer, in which: as organic pigments, preferably styrenes, acrylates or combinations thereof with melting points in the range between 90 ° C. and 180 ° C., but in particular between 110 ° C.-140 ° C., as a binder, preferably starch, polyvinyl alcohol, polyvinyl pyrolidone or a plastic dispersion containing acrylate, styrene or PVAC, and preferably used as inorganic pigments are silicas, aluminum oxyhydrates, kaolins or carbonates. Special paper according to one of claims 1-2, characterized in that the coating is applied with a basis weight of 5-15 g / m ² . Process for the production of a special paper according to one of claims 1-3, characterized in that a paper substrate at least on one side with a film-forming organic Brush pigments and mixture containing binders or is impregnated. A method according to claim 4, characterized in that the mixture is preferably an aqueous dispersion and has the following composition: 20-90% organic pigments, 1-30% binder 0-20% inorganic pigments 0- 1% surfactant wetting agent 0- 5% UV stabilizers 0- 3% water repellent / sizing agent 0-10% plasticizer, in which: as organic pigments, preferably styrenes, acrylates or combinations thereof with melting points in the range between 90 ° C. and 180 ° C., but in particular between 110 ° C.-140 ° C., as a binder preferably starch, polyvinyl alcohol, polyvinyl pyrolidone or an acrylic dispersion containing styrene or PVAC, and preferably used as inorganic pigments are silicas, aluminum oxyhydrates, kaolins or carbonates. Method according to one of claims 4-5, characterized in that the mixture is applied with a basis weight of 5-15 g / m ² . Method according to one of claims 4-6, characterized in that that the mixture is offline, preferably through Brush, applied to the dry paper substrate and the subsequent drying is carried out at a temperature at which no film formation occurs, preferably at a temperature of at most 70 ° C. Method according to one of claims 4-7, characterized in that the blend inline in the paper machine, preferably by brushing, on the not yet finished paper substrate applied and the subsequent drying of the thus treated Substrate is carried out at a temperature which does not yet form a film, preferably in one Maximum temperature of 70 ° C. Printed special paper, characterized in that it has at least one side a layer in which printing ink in filmed or sintered organic pigments and binder is embedded. Printed special paper according to claim 9, characterized in that, apart from the printing ink and paper fibers, the layer has the following composition: 20-90% organic pigments, 1-30% binder 0-20% inorganic pigments 0- 1% surfactant wetting agent 0- 5% UV stabilizers 0- 3% water repellent / sizing agent 0-10% plasticizer, in which: as organic pigments, preferably styrenes, acrylates or combinations thereof with melting points in the range between 90 ° C. and 180 ° C., but in particular between 110 ° C.-140 ° C., as a binder, preferably starch, polyvinyl alcohol, polyvinyl pyrolidone or a plastic dispersion containing acrylate, styrene or PVAC, and preferably used as inorganic pigments are silicas, aluminum oxyhydrates, kaolins or carbonates. Method for producing a printed special paper which has a layer on at least one side in which printing ink is embedded in filmed or sintered organic pigments and binders, characterized by the following steps: Printing on a special paper which has a coating containing film-forming organic pigments and binders applied to at least one side on the side of this coating, Filming the coating by applying heat. A method according to claim 11, characterized in that filming at a temperature in the range between 90 ° C and 180 ° C, but especially between 110 ° C-140 ° C. becomes. Method according to one of claims 11-12, characterized in that that for filming at the same time pressure, preferably a pressure between 0.5-5 bar is applied. Method according to one of claims 11-13, characterized in that that filming in a continuous process, in particular through heated rollers. Method according to one of claims 11-14, characterized in that that filming in a stationary, heatable Press is performed. Method according to one of claims 11-15, characterized in that that the filming immediately after the Printing still in the printing machine or in one with it connected filming unit is carried out. Method according to one of claims 11-16, characterized in that that the filming in contact with the above Layer with a surface is carried out, which a maximum Roughing depth of 0.01 microns. Method according to one of claims 11-17, characterized in that that the filming in contact with the above Layer with a surface is carried out, which a Has a roughness depth in the range between 0.01 and 5 µm. Method according to one of claims 11-18, characterized in that that inkjet printing is possible becomes. Use of the method according to one of the claims 11-19 for producing a print with abrasion-resistant and / or water-resistant surface. Use of the method according to one of the claims 11-19 for the production of an identification or security document, a certificate or the like. Use of the method according to one of the claims 11-19 for the production of paper prints from photographs. Printing device, in particular inkjet printer, with integrated filming device, which also generates pressure, if necessary. Printing device according to claim 23, characterized in that the filming device comprises heated rollers.