EP0183696A1

EP0183696A1 - Recording medium for recording apparatus

Info

Publication number: EP0183696A1
Application number: EP84902911A
Authority: EP
Inventors: Manfred RÖSSLER; Gerhard Winter; Hermann Stiltz
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1983-08-19
Filing date: 1984-07-24
Publication date: 1986-06-11
Also published as: JPS60500015U; WO1985001019A1; DE3329981A1; US4606937A; IT8422278A0; IT1176593B

Abstract

Support de données (10) en papier ou en plastique pour appareils d'enregistrement, sur lequel est placée une couche de contraste (11) et sur celle-ci un revêtement métallique (12) métallisé sous vide et pouvant être brûlé par des électrodes d'enregistrement, en particulier un revêtement d'aluminium. Pour diminuer les traces de grattage et d'abrasion sur la surface du revêtement métallique (12), un lubrifiant finement pulvérisé, pénétrant par diffusion également dans le revêtement métallique (12) et se déposant sur la surface libre de ce dernier, est ajouté à la couche de contraste (11). Le lubrifiant est ajouté à l'agent contrastant de préférence sous forme pulvérulente avant le traitement de celui-ci. Son action est d'une part physique, par une réduction de la friction de glissement sur la surface, et d'autre part chimique, puisqu'il empêche les résidus de combustion provenant de la couche de contraste de s'incruster sur les électrodes d'enregistrement.Data carrier (10) of paper or plastic for recording apparatuses, on which is placed a contrast layer (11) and on this a metal coating (12) metallized under vacuum and can be burnt by electrodes of recording, in particular an aluminum coating. To reduce the traces of scratching and abrasion on the surface of the metallic coating (12), a finely sprayed lubricant, penetrating by diffusion also into the metallic coating (12) and depositing on the free surface of the latter, is added to the contrast layer (11). The lubricant is added to the contrast agent, preferably in powder form before the treatment thereof. Its action is on the one hand physical, by a reduction of the sliding friction on the surface, and on the other hand chemical, since it prevents the combustion residues coming from the layer of contrast from being encrusted on the electrodes of 'recording.

Description

Record carriers for recording devices

State of the art

The invention relates to a recording medium for recording devices according to the preamble of the main claim. Such a record carrier is known, for example, from DE-OS 30 17 450, aluminum being applied as a metal coating on a tape-like carrier. To reduce scratch marks and scratches on the surface of the record carrier, the metal covering has a sliding layer on its surface, which can consist of a metal soap, among other things. After the actual recording medium comprising the carrier, contrast layer and metallization has been completed, the sliding layer is applied to the surface of the metal layer as a further layer. On the one hand, this production requires an additional operation for the application of the sliding layer, on the other hand, this sliding layer can be involved in the recording process Soiling of the writing electrode and the ground contact of the writing device cause, which can lead to a significant impairment of the writing quality as well as to undesirable burns on the ground contact. Furthermore, DE-OS 30 40 485 describes a method for producing a sliding layer on the surface of a recording medium coated with aluminum, in which, when the back of the carrier is coated with one or more nitro lacquer layers, the last lacquer layer is added with one or more several fatty acids is mixed, which reacts with the aluminum layer after the winding up of the recording medium into a roll during a longer aging process and partially converts it into an aluminum soap. On the one hand, this process is complex and can only be used in conjunction with the coating of the back of the recording medium; on the other hand, similarly to the application of a sliding layer to the surface of the metal covering, a layer similar to that described above is formed there, which does not have the desired properties to a sufficient extent.

Advantages of the invention

The recording medium according to the invention for recording devices with the characterizing features of the main claim has the advantage over the described prior art that the desired effect of grinding track and scratch mark reduction is achieved without additional work in the production of the recording medium with greater effectiveness. The lubricant used can be added in the preparation of the agent forming the contrast layer, whereby as Contrast agents are particularly suitable for varnishes and printing inks. Varnishes mainly contain the relatively volatile ethyl acetate as solvent, while printing inks strive for a slower drying process, which is why butyl acetate is used to a greater extent as a solvent. Printing inks, in particular printing inks suitable for gravure printing, are generally richer in filler than varnishes, but there are no fundamental differences between these two common contrast media.

The increase in the grinding track and scratch mark strength of the recording medium according to the invention is achieved by incorporating the lubricant in the vapor-deposited metal layer by means of a diffusion process. The risk of contamination of the writing electrodes and the ground contact is significantly reduced since only small amounts of the lubricant are present on the surface of the metal layer. However, these small amounts are sufficient to achieve the necessary sliding and separating action on the surface of the metal layer, and tests have shown that electrode wear is also greatly reduced. Furthermore, during the burn-out process, the lubricant in the contrast layer becomes chemically effective and prevents or reduces the formation of combustion residues on the writing electrodes by chemical reactions, which likewise lead to deterioration in the writing quality and, due to sharp-edged tips, mechanical grinding and scratch marks on the metal surface.

The effect of known lubricants was limited to grinding marks and scratch marks on the undamaged metal layer due to the application of the electrodes to fight. In contrast to this, the solution according to the invention additionally achieves that the processes which lead to contamination of the electrodes during the burning-out process of the metal layer and subsequently to increased grinding and scratching marks are to be combated. The lubricant introduced into the contrast layer remains on the one hand in the contrast layer and on the other hand reaches the metal layer and the free surface of the metal layer by diffusion. In addition to the physical effect in terms of increasing the lubricity on the surface, the lubricant is also chemically effective within the layers by combating the processes that lead to contamination of the electrode during the burnout process and thereby to increased grinding marks and scratch marks. In addition to reducing the grinding marks due to the sliding effect, the cause of the grinding marks is also combated.

The measures listed in the subclaims permit advantageous developments and improvements of the record carrier specified in the main claim. The use of metal soap as a lubricant, which has led to particularly good results, is particularly noteworthy. Of the metal soaps, in particular, aluminum tristearate and Zn-12-hydroxyl aurate have proven particularly useful as lubricants. Other lubricants for the stated purpose would be, for example, powdery, pasteuse or liquid waxes, fatty acid esters and / or silicone compounds or modified silicone resins. Metal soaps are not only good lubricants but also have good release properties and therefore considerably reduce the build-up of combustion residues and particles detached from the paint surface on the electrode, which comes into contact with the paint surface in a hot state during the burnout process. Metal soaps are advantageous as lubricants according to the invention, also because they are well compatible with customary lacquers or printing inks and are very easy to incorporate. They have no tendency to form within the contrast medium and even reduce the tendency of the other pigments in the contrast medium to settle.

Particularly good effects have been achieved with a contrast layer of a lacquer layer based on cellulose esters with ethyl acetate and / or butyl acetate as a solvent, to which a metal soap in a finely divided, powdery form is added as a lubricant in the liquid state. The contrasting layer can be colored with carbon black, but better effects have still been achieved with the lubricants according to the invention in conjunction with soluble dyes. A matt surface of the contrast layer, which also contributes to a matt surface of the overlying metal layer, is preferably achieved by admixing colorless pigments, in particular diatomaceous earth. Other colorless matting agents would preferably be calcium carbonate or amorphous silica. Further particularly advantageous embodiments of the invention result from the remaining subclaims and from the description of the exemplary embodiments. drawing

The basic structure of a recording medium for recording devices according to the invention is shown schematically in the drawing and explained in more detail in the following description.

Description of the embodiments

In the figure, a recording medium for recording devices is shown in tape form, which is on a carrier

10 carries a contrast layer 11 and over it a metallic covering which can be burned out by one or more electrodes. An aluminum coating is preferably suitable as the metal layer, but instead, for example, a zinc-cadmium layer could also be used. The carrier 10 preferably consists of a paper web, but a plastic film can also be used as the carrier. The contrast layer 11, which contains at least one polar solvent, preferably consists of a lacquer which is applied by knife coating or roller coating. Instead of a lacquer, however, a printing ink can also serve as a contrast layer, which is preferably applied using the gravure printing process. The metal coating 12, in particular an aluminum coating, is vacuum-deposited onto the contrast layer 11 in a thickness of approximately 0.01 to 0.1 / μm, preferably in a thickness at the lower limit of 0.01 / μm. The contrast layer

11 consists of a lacquer layer in a thickness of 1 to 5 / um, preferably in a thickness of 3 / um and is applied in a roll coating process to a paper tape with a thickness between 60 and 100 / um, preferably of 60 um. The ones visible in the drawing Thickness ratios therefore only serve the principle

Explanation of the structure of the recording medium and do not correspond to the actual thickness ratios of the different layers.

The essence of the invention consists in introducing finished lubricants, in particular a metal soap in powder form, into the contrast layer in finely divided form instead of subsequently creating a separate surface sliding layer on the metal covering. The lubricant partly remains in the contrast layer, another part gets into the metal layer and to the surface of the metal layer by diffusion. In this way, the double effect of the lubricant is achieved on the one hand in physical terms by increasing the lubricity and on the other hand in chemical terms by preventing deposits on the electrode which otherwise occur during the burning process. In addition to metal soaps, suitable lubricants are, in particular, siloxane combinations, polyethylene waxes and silicone oils, which can also be added to the contrast medium in liquid form.

The recording media according to the invention preferably use lacquer systems as contrasting layers based on cellulose esters such as cellulose acetobutyrate, which are pigmented with diatomaceous earth to achieve a matt surface and to improve the writing properties. Good results were achieved with 3 to 10 Gev. % Diatomaceous earth as matting agent with a total solids content of 10 to 23 gev. %. In these recording media, a proportion of 0.1 to 5% by weight, preferably 0.5 to 1.5% by weight, of a metal soap is added to the contrast layer 11 as a lubricant, the proportions being related on the wet weight of the contrast medium. Neutral-reacting metal soaps are preferably used as lubricants, in particular soaps of the metals Al, Zn, Mg and Ca. Both soaps of saturated and unsaturated fatty acids can be considered.

The following two compositions gave particularly good results: A first exemplary embodiment contained on a carrier 10 made of paper as a contrast layer 11 a lacquer which, based on the liquid state, had 10%. % Cellulose acetobutyrate, 5.5% % Diatomaceous earth as matting agent, 2% by weight soluble dye and 1.5 gev. % Al tristearate contained as a lubricant. In another exemplary embodiment, particularly good results have been achieved with an arrangement comprising a carrier 10 made of paper, the contrast layer 11 of which likewise consisted of a lacquer layer with 10 gev. % Cellulose acetobutyrate (CAB) as binder 7.5% by weight diatomaceous earth as matting agent, again 2 gev. % soluble dye and 1% by weight Zn-12-hydroxylaurate as a lubricant.

Claims

Expectations

1. Record carrier for recording devices, in particular in tape form, with a carrier made of paper or plastic, a contrast layer applied thereon, containing at least one polar solvent, and a vapor-deposited, burnable metallic coating, preferably an aluminum coating, characterized in that the contrast layer (11) a lubricant in finely divided form is added.

2. Record carrier according to claim 1, characterized in that the lubricant consists of a metal soap.

3. Record carrier according to claim 1 or 2, characterized in that the contrast layer (11) consists of a lacquer layer based on cellulose esters with ethyl acetate and / or butyl acetate as a solvent, which in the liquid state is mixed with a metal soap in a finely divided form as a lubricant.

4th Record carrier according to one of the preceding claims, characterized in that the lubricant consists of powdered Al tristearate and / or powdered Zn-12 hydroxyl aurate.

5. Recording medium according to one of the preceding claims, characterized in that 0.1 to 5% by weight, preferably 0.5 to 1.5% by weight, of a metal soap is added to the contrast layer (11) as a lubricant, based on the wet weight of the Contrast agent.

6. Record carrier according to one of the preceding claims, characterized in that the contrast layer (11) contains diatomaceous earth as a colorless pigment, preferably 3 to 10% by weight diatomaceous earth, with a total solids content of 10 to 23% by weight, based on the wet weight of the contrast weight .

7. Recording medium according to one of the preceding claims, characterized in that the contrast layer (11) consists of a lacquer which in the liquid state is approximately 10% by weight cellulose acetobutyrate (CAB) as a binder and approximately 5.5% by weight diatomaceous earth as a matting agent contains about 2% by weight of soluble dye and about 1.5% by weight of Al tristearate as a lubricant.

8. Record carrier according to one of claims 1 to 6, characterized in that the contrast layer (11) consists of a lacquer which in the liquid state is about 10% by weight of cellulose acetobutyrate (CAB) as a binder, about 7.5% by weight. Diatomaceous earth as a matting agent, about 2% by weight of soluble dye and about 1% by weight of Zn-12-hydroxylaurate as a lubricant.