Patent FR-2992663-A1 (FR)
Title: Making sheet used in electroconductive product e.g. switch, by preparing multilayer structure including plastic film, non-stick coating and base layer, laminating surface of substrate and structure and removing film and coating from layer
Inventor: DEPRES GAEL
IPC: B32B29/06
Filed: 2012-07-02
Abstract: The method comprises preparing a multilayer structure (12) comprising a plastic film, a non-stick coating (16) and a base layer, cutting the multilayer structure in the form of band, laminating, using a thermofusible adhesive, a surface of a substrate of a sheet (10) and/or a surface of the multilayer structure provided on opposite side of the plastic film, and removing the plastic film and the nonstick coating from the base layer. The substrate is made of a tracing paper, and has a surface that is partially covered with superposed electroconductive layers. The method comprises preparing a multilayer structure (12) comprising a plastic film, a non-stick coating (16) and a base layer, cutting the multilayer structure in the form of band, laminating, using a thermofusible adhesive, a surface of a substrate of a sheet (10) and/or a surface of the multilayer structure provided on opposite side of the plastic film, and removing the plastic film and the nonstick coating from the base layer. The substrate is made of a tracing paper, has a surface that is partially covered with superposed electroconductive layers, and comprises a filler intended to improve a thermal diffusivity, a humid resistance and a fire-proof property of the sheet. The non-stick coating is disposed between the plastic film and the base layer. The base layer is intended to be covered with an electroconductive layer by an additional step consisting of depositing an electroconductive film on the base layer, performing thermal pretreatment on the sheet to remove water, printing the base layer with an ink having electrical properties and subjecting the base layer to plasma treatment. The base layer is a printable layer made from a binder at a concentration of more than 30 wt.%, and extends over an interior surface of the plastic film. The printable layer is optionally subjected to a heat treatment to form an electrically conductive ink layer. The printable base layer comprises a binder, optionally a co-binder, and pigments having an average diameter of = 2 mu m, is formed of two sub-layers having different or identical composition, and has a transparency. The base layer is printed by an ink-jet printing, a gravure printing, a flexographic printing, a serigraphic printing or an offset printing. The electrically conductive ink comprises nanoparticles or metallic microparticles, nanoparticles or carbon microparticles, and/or a conducting polymer. The sheet further comprises a metallic film and/or a barrier layer provided between the substrate and the base layer, and has a zone including an internal layer, which is formed by the base layer and extends on the substrate of the sheet. The heat treatment is performed in an oven on a hot plate, a photonic oven, or an infrared drier. The adhesive comprises a mono-component or bi-component polyurethene adhesive with or without solvent. The multilayer structure and the substrate are laminated on an interior surface of the sheet. The plastic film has a dimension from its length and width, which is less than a dimension corresponding to the surface of the sheet. The multilayer structure is applied on the substrate by an embosser press, which is intended to apply a pressure in the zone or by a hot stamping press, which softens the adhesive. The sheet is produced in a drying section of a paper machine. Independent claims are included for: (1) a process for fabricating an electroconductive product; and (2) an electroconductive product.