US-12618137-B2 - Coating method and device

US12618137B2US 12618137 B2US12618137 B2US 12618137B2US-12618137-B2

Abstract

The invention relates to a method and a device for coating a strip-type, flexible, dielectric substrate with a metal layer on a coating roll over which the substrate is guided in the longitudinal direction of the substrate during the coating process. In order to improve the adhesion of the substrate on the coating roll during the coating process, the substrate is charged. The substrate is coated with a first metal layer, wherein, in the longitudinal direction of the substrate, at least one free strip remains which is not coated with the metal layer, and the coated substrate is provided with a second metal layer.

Inventors

Michael Mücke

Assignees

BÜHLER ALZENAU GMBH

Dates

Publication Date: 20260505
Application Date: 20210625
Priority Date: 20200626

Claims (9)

1 . A method for coating a strip-type, flexible, dielectric substrate with a metal layer on a coating roll over which the substrate is guided in the longitudinal direction (L) of the substrate during the coating process, comprising the steps of: (a) charging the substrate to improve adhesion of the substrate on the coating roll during the coating process, (b) coating the substrate with a first metal layer, wherein, in the longitudinal direction (L) of the substrate, at least one free strip remains which is not coated with the metal layer, (c) coating the coated substrate with a second metal layer, wherein the method has a step for re-charging the substrate at least before one of the steps for coating the substrate with the second metal layer or a further metal layer, wherein, during coating of the coated substrate in step (c) an air pocket is formed between the coating roll and the portions of the substrate coated in step (b) to support cooling of the substrate, wherein a gaseous medium is introduced in these portions to increase the cooling effect of the air pocket.
2 . The method according to claim 1 , wherein the at least one free strip is provided in an environment of at least one longitudinal edge of the substrate.
3 . The method according to claim 1 , wherein at least two free strips remain, wherein the two longitudinal edges of the substrate are each encompassed by one of the free strips, and the free strips are spaced apart in the width direction by a distance which remains constant in the longitudinal direction (L) of the substrate.
4 . The method according to claim 1 , further comprising a step (a1) carried out before step (b) for treating the portions of the surface of the substrate to be coated, on which portions the free strips are to remain, in such a way that the application of the metal layer in the free strips is avoided, wherein the treatment comprises at least one of the following: applying oil or other media that vaporize in a vacuum after a certain time, using a vaporization method or an offset printing method; covering by means of masking; action of an air flow to blow a metal vapor; suctioning a metal steam; applying a protective medium; in-situ evaporation of the metal application; and creating regions of reduced conductivity.
5 . The method according to claim 1 , wherein a surface of the substrate is coated in steps (b) and the surface of the substrate opposite the surface coated in step (b) is coated in step (c).
6 . The method according to claim 5 , wherein, before step (c), portions of the opposite surface of the substrate to be coated in step (c), on which portions the free strips are to remain, are treated in order to ensure that the free strips remain free, wherein the free strips of the opposite surface correspond to the portions of the surface remaining in step (b).
7 . The method according to claim 5 , wherein the surface of the substrate coating in step (b) and the surface of the substrate opposite the surface of the substrate coated in step (b) are coated alternately with a first and optionally subsequent layers.
8 . The method according claim 1 , wherein the method further comprises coating the substrate with further metal layers.
9 . The method according to claim 1 , wherein the substrate is coated by means of a vacuum vapor deposition method.

Description

The present invention relates to a method and a device for coating strip-type, flexible, dielectric substrates, in particular for repeated coating of such substrates. When strip-type substrates, such as a film, are coated on a coating roll, it is known to provide the substrate with charge before coating in order to improve the adhesion of the substrate on the coating roll. The substrate is charged, for example, with the aid of an electron beam, which is directed onto the substrate before contact with the coating roll. The charge causes a strong adhesion of the substrate on the roll, thereby significantly improving the cooling of the substrate during the coating process. This makes it possible to increase the coating rate and/or to reduce the thickness of the substrate. Such a method is known, for example, by the name SuperBias. EP 1 686 197 B1 describes a vacuum vapor deposition method and a device, wherein the layer made of insulating material which is to be coated is brought into close contact with a cooling roll by means of charging. The charging of the substrate requires a dielectric substrate; conducting substrates cannot be charged by the electron beam. This also applies to substrates provided with a metal coating in a preceding step. Such a coating also causes an intrinsically dielectric substrate to be conductive, which no longer allows subsequent charging or reduces the effect of previous charging. For this reason, the advantages of the known methods can be achieved only in the case of a single coating, that is to say, only one-sided coating. It is therefore an object of the invention to also achieve the advantageous effects of charging for substrates which have been metal-coated in a preceding process step. This is to make it possible in particular to also improve the coating process for processes in which a substrate is coated repeatedly, wherein at least one of the coating processes comprises coating with a metal coating, such as multiple or double-sided coatings. An improvement is thus also to be achieved for the coating process following a metal coating. These objects are accomplished with the features of the invention according to the independent claims; the dependent claims define embodiments of the invention. It is a basic idea of the present invention, in the case of the metal coating of a substrate, not to coat the substrate over its entire width, but to provide at least one longitudinal strip of the substrate along which no coating takes place. These strips of the substrate that are not provided with a metal layer can then maintain the previous charge or be provided with new charge, so that the adhesion of the substrate on the coating roll remains improved at least along the free strip. The subsequent further coating can then be carried out on the same surface or on the rear side, preferably again in the portions of the substrate coated during the first coating process. In particular, the invention provides a method for coating a strip-type, flexible, dielectric substrate with a metal layer on a coating roll over which the substrate is guided in the longitudinal direction of the substrate during the coating process. To improve the adhesion of the substrate on the coating roll during the coating process, the substrate is charged. The substrate is coated with a first metal layer, wherein, in the longitudinal direction of the substrate, at least one free strip remains which is not coated with the metal layer, and the coated substrate provided with a second metal layer. The at least one free strip is preferably provided in an environment of at least one longitudinal edge of the substrate, wherein preferably at least two free strips remain, wherein the two longitudinal edges of the substrate are each encompassed by one of the free strips, and the free strips are spaced apart in the width direction by a distance which preferably remains constant in the longitudinal direction of the substrate. Before step (b), a step (a1) for treating the portions of the surface of the substrate to be coated, on which portions the free strips are to remain, can be carried out in such a way that the application of the metal layer in the free strips is avoided. The treatment can comprise at least one of the following: applying oil, or other media that vaporize in a vacuum after a certain time, using a vaporization method or an offset printing method; covering by means of masking; action of an air stream to blow the metal vapor; suctioning the metal vapor; applying a protective medium; in situ vaporization of the metal layer; and creating regions of highly reduced conductivity. In step (b), a surface of the substrate can be coated, wherein in step (c), the same surface of the substrate is coated with a further layer. Also, a surface of the substrate can be coated in step (b) and the surface of the substrate opposite the surface coated in step (b) can be coated in step (c). Before step (c), portions of the opposite