RECORDING MATERIAL

Abstract: The invention relates to a recording material for the inkjet method having a particularly glossy surface, a substrate material having a metal layer on at least one of its surfaces and it being possible for this metal layer additionally to be provided with a protective layer. The material thus obtained carries an ink-accepting layer on one of the following surfaces: 1. on the metal layer, 2. on the protective layer covering the metal layer, 3. on that surface of the substrate maerial which faces away from the metal layer. When an image is recorded on the ink-accepting layer on a commercial inkjet plotter, particularly interesting reflecting colour effects are obtained, in particular colours such as silver, gold, golden red, etc. being produced, which are not achievable by means of a conventional inkjet recording method.

Description: Description Recording Material The invention relates to an improved recording material to meet the requirements of the inkjet process. Such recording material are known in principle. They are paper or transparent or dull plastics films. These mate¬ rials, in particular the plastics films, carry an ink- accepting layer on at least one of their surfaces. These are generally hydrophilic coatings which are applied to the substrate in a thickness of between 2 and 50 μm. Such layers are particularly suitable for accepting the gene¬ rally aqueous inks. WO 92/0772 describes the coating of a substrate material with a mixture of a cross1inkable and a liquid-absorbing polymer, a partially permeable network being formed in the layer after complete reaction of the said polymers. WO 93/0486 discloses an ink-accepting layer which is com¬ posed of the following components: (1) a vinylpyrrol i- done, (2) a polyester, (3) an alkylene oxide polymer, (4) a polyvinyl alcohol and (5) a polyether. The layer exhi¬ bits particularly good acceptance properties for aqueous inks. EP-A-524 626 describes a recording material having a layer which consists mainly of porous pseudoboehmite. This coating has the advantage of particularly rapid drying of the ink. The use of coloured inks in addition to black ink has be¬ come established in the production of recordings, in par¬ ticular image recordings. A wide range of colour effects is achievable by suitable mixing of the primary colours cyan, magenta, yellow and black. In some cases (graphics, advertising, labels), particularly glossy, reflecting co- lour effects are desirable. Such effects are not achiev¬ able by means of conventional known recording materials. It is the object of the invention to provide a recording material for inkjet processes on which particularly glos¬ sy recordings and/or colour effects are achievable with conventional inks. This object is achieved by a recording material for ink¬ jet recordings having a substrate material which has, at least on one of its surfaces, a metal layer which may be additionally covered with a protective coating, and, either on this metal layer or on the protective layer co¬ vering the metal layer or, in the case of a transparent substrate material, optionally on the opposite surface of the substrate material, a transparent recording layer whose gloss is over 70% when measured according to DIN 67 530 at an angle of 20°, 60° and 85°. It is usual to measure the gloss at different angles, de¬ pending on the gloss. Relatively dull surfaces are usual¬ ly measured at 85° and more highly glossy surfaces at 20°. The recording material according to the invention has a gloss of more than 70%, preferably of more than 80%, at all conventional measuring angles. A gloss of more than 90% at the measuring angles 60 and 85° and more than 85% at a measuring angle of 20° is very particularly preferred. The gloss of the recording material is measured on the recording layer according to DIN 67530 using commercial gloss measuring apparatuses, for example by means of an apparatus obtainable under the name "detectometer" from the company Dr. Lange. The measurement is carried out against the standard gloss master (standard A). To achieve this gloss of the recording material, the transparent substrate material is provided with a smooth reflecting metal layer on at least one surface by any dessired method. Suitable preferred metals are aluminium, zinc, nickel, chromium, copper, gold, silver or the al¬ loys thereof. The application is preferably effected by vapour deposition at reduced pressure or by cathode sput¬ tering over the substrate material arranged in a chamber. The metal layer may also be composed of several indivi¬ dually applied layers in order to obtain the desired thickness. The thickness of the metal layer is preferably 10 nm to 300 nm. In order to achieve the desired effect of the metal layer on the surface gloss of the recording layer, the sub¬ strate material should have as smooth a surface as pos¬ sible. This can be achieved by means of a coating on a substrate material, for example paper. A particularly suitable transparent substrate material comprises pla¬ stics films of thermoplastic polymers, for example poly¬ ester films. Transparent papers are also suitable as sub¬ strate material . In order to protect the metal layer from being scratched, it may additionally be provided with a protective layer. Suitable polymers for this purpose are, for example, poly(meth)acrylates, polyvinyl acetates or copolymers thereof. The transparent recording layer for inks contains a hy¬ drophilic film-forming polymer. Suitable polymers are polyvinyl alcohol (PVA), polyvinylpyrrol idone (PVP), cel¬ lulose derivatives, (meth)acryl ic acid derivatives, poly¬ vinyl acetate or copolymers thereof and mixtures of such substances. The recording layer may have a thickness of 2 μm to 50 μm. This transparent recording layer for inks can, according to the invention, be applied to the following surfaces: 1. to the metal layer 2. to the protective layer covering the metal layer 3. in the case of transpatent substrate material, optio¬ nally to that surface of the substrate material which faces away from the metal layer. Since the adhesion of the recording layer to the metal layer is not completely sufficient in some cases, embodi¬ ments 2 and 3 are preferred. In the case of embodiment 3, the effect of the metal lay¬ er also occurs through the transparent substrate material towards the surface of the recording layer. Examples Example 1 A 100 μm thick polyethylene terephthalate film is pro¬ vided on one side with an about 50 nm thick aluminium layer by vapour deposition at reduced pressure. The other surface of the film is then coated with the following so¬ lution: Coating composition: 85 kg of water 15 kg of polyvinylpyrrol idone (PVP) This coating solution is applied with the aid of a 0.8 mm wire-wound doctor to that surface of the film which faces away from the metal layer and is then dried for 2 minutes at 160°. The resulting coating weight of this ink-accep¬ ting layer is about 9 g/m . The recording of an image on this final layer on a commercial inkjet plotter, for example Canon BJC 800, gives particularly interesting re¬ flecting colour effects, in particular colours such as silver, gold, golden red, etc. being produced, which are not achievable by means of a conventional inkjet recor¬ ding method. Example 2: A 100 μm thick polyethylene terephthalate film is pro¬ vided with an aluminium layer by vapour deposition in the same manner as in Example 1. The coating solution de¬ scribed in Example 1 is then applied to this aluminium layer in the same manner. Here too, recording of an image gives the same interesting colour effects. Example 3: A polyethylene terephthalate film is coated by vapour de¬ position on one side in the same manner as in Example 1. The following protective coating is then applied to this metal layer: Coating composition: 75 kg of methyl ethyl ketone 10 kg of propylene glycol methyl ether 15 kg of commercial acrylate polymer (solid) This coating solution is applied to the metal layer by means of a 0.4 mm wire-wound doctor and then dried for about 2 minutes at 160°C. The resulting coating weight of this second layer is about 1.5 g. The ink-accepting layer is applied to this second layer as described in Example 1. Here too, recording of an image on this final layer on a commercial inkjet plotter gives the same reflecting co¬ lour effects.

Claims: Claims 1. Recording material for the inkjet method having a substrate material which has a metal layer at least on one of its surfaces, it being possible for this metal layer additionally to be covered with a protective coating, and has, either on this metal layer or on the protective layer covering the metal layer or, in the case of transparent substrate material, optionally on the opposite surface of the substrate material, a transparent or slightly dull recording layer, the gloss, measured on the surface of this recording layer, according to DIN 67530 having a value > 70% when measured at an angle of 20°, 60° and 85°. 2. Recording material according to Claim 1, charac- terized in that the gloss has a value > 80% at an angle of 20°, 60° and 85°. 3. Recording material according to Claim 1, charac¬ terized in that the gloss has a value > 90% at an angle of 60 and 85° and a value > 85% at an angle of 20°. 4. Recording material according to any of Claims 1- 3, characterized in that the substrate is a plastics film. 5. Recording material according to any of Claims 1- 4, characterized in that the metal layer contains alu- minium, zinc, copper, nickel, chromium, gold, silver or alloys thereof. 6. Recording material according to any of Claims 1- 5, characterized in that the substrate material is a transparent polyester film. 7. Recording material according to any of Claims 1- 6, characterized in that the recording material contains a hydrophilic film-forming material. 8. Recording material according to any of Claims 1- 7, characterized in that the hydrophilic material con- sists of PVA, PVP, cellulose derivatives, (meth)acrylic acid derivatives, vinyl acetate, copolymers thereof or a mixture of these substances. 9. Recording material according to any of Claims 1- 8, characterized in that the metal layer is additionally covered with a protective layer. 10. Recording material according to any of Claims 1- 9, characterized in that the protective layer is a (meth)aerylate polymer or copolymer.

Inventors: KOCH PETER, LIEBLER RALF, KOCH, PETER, LIEBLER, RALF
Applicants: KOCH PETER, LIEBLER RALF, RENKER GMBH & CO KG, KOCH, PETER, LIEBLER, RALF, RENKER GMBH & CO. KG
Application year: 1995
Main classification: B41M5
IPC codes: B32B27, B41M1, B41M5