EP1185989B1 - Magnetic coating, coating method with same and coating apparatus therefor - Google Patents

Magnetic coating, coating method with same and coating apparatus therefor Download PDF

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Publication number
EP1185989B1
EP1185989B1 EP00949523A EP00949523A EP1185989B1 EP 1185989 B1 EP1185989 B1 EP 1185989B1 EP 00949523 A EP00949523 A EP 00949523A EP 00949523 A EP00949523 A EP 00949523A EP 1185989 B1 EP1185989 B1 EP 1185989B1
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EP
European Patent Office
Prior art keywords
particles
coating
binder
medium
applying
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EP00949523A
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German (de)
French (fr)
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EP1185989A1 (en
Inventor
Claude Texier
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Magnesia Industries Inc
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Magnesia Industries Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/14—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates
    • H01F41/16—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates the magnetic material being applied in the form of particles, e.g. by serigraphy, to form thick magnetic films or precursors therefor

Definitions

  • the present invention relates mainly to a magnetic coating, to a process for coating external surfaces, in particular sheet materials or rolls, with such a coating, and to a coating apparatus implementing said method.
  • the invention applies in the field of play, especially for puzzles, board games, educational or didactic materials, in the field of stationery, decoration or building: wallcovering, removable attachment to the using magnetic elements (magnets in English terminology), signaling or magnetic veneer, coating plastered surfaces, for example plasterboard surfaces, or electromagnetic shielding.
  • the invention also applies to the field of advertising, for example for outdoor and indoor posters or posters.
  • the present invention aims to overcome these disadvantages, by providing a magnetic coating generating an anisotropic medium for optimizing the magnetic attraction and sliding forces exerted by the coating, this coating being able to be applied to any support, and in particular paper, cardboard, sheets of material flexible or rigid plastic, wallpaper, walls and others.
  • the magnetic efficiency of the forces exerted by the particles in anisotropic medium is 25 to 30% greater than that obtained in an isotropic medium.
  • the subject of the present invention is a magnetic coating capable of being spread out substantially regularly on a surface, in which conductive particles oriented by a prior magnetization according to an inductive electromagnetic field, in particular ferromagnetic particles such as particles of iron oxide, are embedded in a binder.
  • the coating according to the invention makes it possible to carry out an electromagnetic shielding by firstly ensuring the confinement of the electromagnetic waves emitted in a room and, secondly, by limiting the penetration of electromagnetic waves. in this piece.
  • non-ferromagnetic conductive particles for example copper particles
  • the adhesive used as the main binder is preferably electrically conductive.
  • the conductive particles are rod-shaped in order to increase their ability to orient themselves according to the inductive electromagnetic field.
  • said binder is an adhesive resin, in particular a hot melt glue (hot melt in English terminology), a cold glue or a paint.
  • the adhesive resin is preferably non-conductive of electricity. It is possible, for example, to use dispersing glues, especially acrylic, vinyl acetate, vinyl ethylene acetate copolymer or acrylic styrene, solution-type glues.
  • vinyl acetate acrylic or styrene acrylic, vegetable glues including starch, dextrin or casein or, advantageously hot melt glues made in particular on an ethylene vinyl acetate, ethylene acrylic, polyolefin, styrene butadiene or styrene isoprene basis.
  • the present invention also relates to a process for coating such a coating on a backing support, comprising a step of applying a main binder to the support guided by a conveyor belt, a controlled distribution and distribution step uniformity of the charge of conductive particles in the resin coupled to a step of orientation of the particles by magnetization, followed by a demagnetization step, a step of covering the particles by deposition of a complementary binder, and a drying step of the whole.
  • the magnetization step is followed by a demagnetization step, so as not to disturb the subsequent steps, and the drying step is followed by a step of remagnetization of the particles.
  • An advantageous embodiment consists of spraying an adhesive resin as a binder for covering the particles and laminating a support on the upper surface thus formed to serve as a frontal support.
  • Any type of support may be used as a front support, namely: cardboard, paper, fabric, flexible or rigid plastic sheet, etc., the nature of the front support may be identical or different from that of the back support.
  • the covering step may advantageously consist in spraying a varnish as a complementary binder.
  • the subject of the invention is also a coating apparatus for implementing the method according to the invention, comprising means for feeding the support, feeding continuously or discontinuously, depending on whether the support is in roll or in sheets, means for applying a main binder by pressure rollers or by at least one nozzle, coupled to heating means, a particle reservoir coupled to a sprinkler for distributing the charge of particles, means for distributing the charge particles in the main binder, electromagnetic means for producing an anisotropic magnetic particle magnetization field, a sprayer for depositing the complementary binder, and drying means.
  • the sprinkler is programmed to deliver the quantity of powder corresponding to the charge density chosen, preferably between 100 and 900 g / m 2
  • the binder application means preferably deliver from about 10 to 50 g / m 2 of product
  • the distribution means are constituted by a system of vibrating screens or by at least one dosimeter, able to form particular patterns by masking
  • the electromagnetic magnetization means are formed by an electromagnet.
  • the coating apparatus shown has different continuous work stations used in combination, alternately or optionally.
  • the apparatus is a single-sided device, it being understood that double-sided devices are not outside the scope of the present invention.
  • the non-limiting example presented describes the coating of a wallpaper to illustrate the operation of the apparatus.
  • the apparatus comprises a backing roll for feeding a backing paper 11, rotated by known means, the paper being guided on a continuous conveyor belt 20 driven in translation at the same speed by rotary elements 21.
  • linear speed is for example between 20 and 250 m / min., preferably between 30 and 150 m / min.
  • the strip 20 Opposite the strip 20 are means for applying a hot melt glue, in the form of a lip nozzle 30 coupled to heating means 31, and a press roll machine 40 for application of a glue 12 cold or hot melt.
  • the binder application means preferably deliver about 10 to 50 g / m 2 of product, preferably about 35 g / m 2 .
  • One or other of these glue distribution means is used depending on the nature of the glue.
  • the temperature of implementation of hot melt glues at the moment of magnetization, must be lower than the Curie temperature of the ferromagnetic material used.
  • the application temperature is between 140 and 190 ° C.
  • a roller type machine such as a machine comprising a 3960 Multiscan® generator sold by NORDSON Company connected by automatic heating pipes to automatic guns marketed by this company under the reference H20. The adhesive flows between two rollers 40 and flows through a calibrated space formed between these rollers.
  • a reservoir 50 of particles 13 coupled to a sprinkler 51 is then provided for the distribution of ferromagnetic particles in powder form.
  • the sprinkler is programmed to deliver the quantity of powder corresponding to the chosen charge density, the mixture of a binder typically a paint or an adhesive with ferromagnetic particles forming a charge in the binder corresponding to 200 to 850 g per square meter.
  • iron oxide preferably substantially equal to 800 g per square meter of iron oxide.
  • the maximum amount of ferromagnetic charge that can be accepted by the binder is used, for example six units by weight of ferromagnetic powder for two units by weight of binder.
  • any ferromagnetic material likely to have the desired particle size and stability, especially chemical, over time can be used.
  • soft iron, hardened iron, ferrite, any iron oxide, ferromagnetic rare earths, samarium, barium or cobalt may be used.
  • coated iron particles are used by a protective material against corrosion, for example by a layer of cobalt. It is also possible to use chromium, chromium oxide and the particles used for coating magnetic tapes.
  • the iron oxide particles used are in the form of elongate rods and have a low granularity so as to obtain a smooth surface state. Excellent results were obtained with iron oxide whose particle size was equal to 24 microns, the lower particle sizes also being suitable. If the granular surface condition is acceptable, it is possible to use larger particle sizes, for example between 25 and 300 ⁇ m.
  • a vibrating screen system (not shown) is coupled to the sprinkler 51 to evenly distribute the particles on the backed-up backing paper.
  • a programmable dosimeter may be used to adjust the amount of powder to be deposited. This deposit can be performed with predetermined patterns by masking using pre-cut screens.
  • a magnetic field induced by an electromagnet 60 is created in order to orient by magnetization the particles just deposited in the adhesive resin, that is to say before the solidification of the adhesive.
  • the use of a hot melt glue in the exemplary embodiment is particularly advantageous because it can easily control the opening and closing.
  • the magnetic field is formed between the sprinkler and the distribution means. This solution is advantageous when, depending on the nature of the powder used, a phenomenon of "wicking" may affect the regularity of deposit on the paper.
  • the magnetization is carried out by magnetically polarizing the particles.
  • the coated paper passes into the gap of the electromagnet 60 generating a field Magnetic substantially uniform over the entire width of the paper is used for example an electromagnet generating an intense magnetic field substantially equal to 0.5 Tesla.
  • the viscosity of the coating according to the present invention as well as the amplitude of the magnetic field are such that the migration of the magnetic particles outside the binder and their bonding in the gap of the electromagnet is carefully avoided.
  • guiding means prevent the coated paper of the coating according to the present invention from sticking to one of the poles of the magnet, in the case of the use of a permanent magnet.
  • the coated paper then passes under a degaussing apparatus 70, disposed immediately downstream of the electromagnetic magnetization means.
  • the use of a paint as a binder may be advantageous in providing a desired color. But ferromagnetic particles can change the color of the paint. If this effect is not desired, it can be covered by one or more layers of paint free of ferromagnetic charge.
  • a sprayer 80 then deposits the complementary binder. The flow rate of this sprayer is adjusted so that all the particles are embedded in this binder.
  • This binder can also be a varnish, for example translucent if it is desired to keep the bottom view of the back paper.
  • a front paper support is then to be deposited in this example, and the sprayer 80 delivers in this case a glue as a complementary binder.
  • the front support feed 14 is also performed by a uncoiler roll 90 coupled to pressure rollers 91 on the conveyor belt.
  • a drying tunnel 100 alternately heating rollers, and a final magnetizer 110, arranged downstream of the drying tunnel, are provided.
  • the magnetizer is a drum coupled in rotation to the conveyor belt, alternating south and north poles according to a previously calculated magnetic pitch.
  • the speed of scrolling and magnetization is of the order of 80 m / min.
  • the applied voltage is of the order of 2000 to 3000 V, delivering a field of 8000 to 9000 gauss, for paper widths between 700 and 1400 mm.
  • a final winding roll 120 provides a roll of the product obtained by the process of the invention.
  • an electromagnetic radiation shield it is advantageous to ensure a sufficient charge of ferromagnetic particles to make the coating according to the present invention conductive, at least at the frequencies that it is desired to eliminate.
  • non-ferromagnetic conductive particles for example copper, are used in addition to or in place of the ferromagnetic particles to form a shield or a Faraday cage.
  • Such shielding can protect electronic equipment, including telecommunications equipment and computer equipment, external disturbances and indiscretions by preventing the listening of electromagnetic signals emitted by this type of equipment in operation.
  • the coating apparatus alternatively of the batch feed type, also has different workstations used in combination, alternately or optionally.
  • the paper is fed sheet-by-sheet 21 on the conveyor belt 20 from a feed tray 15, and the back-up feed 24 is also performed by a sheet-fed feed tray 16 coupled with pressing rolls. 17.
  • the feed tanks and the particle charge distribution means are controlled by an automated dispensing system (not shown) known to those skilled in the art and set at a scroll rate.
  • the device glues for example 90 cartons per minute, each carton having a surface of 40 cm by 55 cm.
  • the binder application means, 30 and 40, and the complementary binder 80, identical to those described above, are set by an optical photocell sequential controller 25, connected to the automated distribution system.
  • the final magnetizer 111 is in the form of an electromagnet and the storage system is in the form of a tray 121 capable of stacking the sheets coated by the apparatus according to the invention, by examples of paper sheets decorated or not, cardboard, plastic plates or the like.
  • the invention is not limited to the embodiments described and shown.
  • the method according to the invention also makes it possible to adapt the thickness of the coating according to the basis weight of the two sheets to be glued. For example, laminating a sheet weighing 90 g on a sheet of the same thickness or thicker requires about 90 to 120 g of coating.
  • the magnetized coating of the magnet can also be adapted under the same conditions. In other words, the thickness of the coating can be perfectly adapted to the aesthetic effect, weight, magnetization force and economic cost that it is desired to give.
  • Zone magnetization can be achieved by magnet gaps having the shape of the desired areas either by employing a set of electromagnets arranged in a matrix manner and feeding only
  • a support typically a cardboard or a plastic sheet
  • the coating according to the present invention so as to allow the stacking of parts.
  • a first face of the support receives a non-magnetic coating, the opposite face receiving a coating capable of being magnetized.
  • the two faces receive a coating which is thereafter permanently magnetized.
  • the apparatus according to the invention advantageously comprises means for cutting the coated support, for example to form "magnet" type elements (magnet in English terminology) comprising, after cutting, a support portion relative to a subject or adapted to receive, for example by gluing, another support relating to this subject.
  • the magnets obtained are held on any metal surface, for example a refrigerator door or any surface (paper, cardboard, etc.) covered with a metal coating (coating containing metal powder in filings or other) or integrating a totally or partially metallic surface (strip, grid or other), by the exercise of the magnetic forces created between these magnets and said metal surface.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)
  • Paints Or Removers (AREA)
  • Coating Apparatus (AREA)
  • Paper (AREA)

Abstract

The invention seeks to provide a magnetized coating suitable for exerting durable magnetic forces. To do this, the method of the invention consists in spreading conductive particles ( 13 ) on a medium ( 11 ), the particles being directed by prior magnetization along an inducing magnetic field and being embedded in a binder ( 12 ). The coating apparatus for implementing the method of the invention comprises means ( 10, 15 ) for feeding the medium ( 11 ) onto a conveyor ( 20 ), means for applying a main binder ( 12 ) via presser rollers ( 40 ) and via at least one nozzle ( 30 ), said means being coupled to heater means, a tank ( 50 ) of particles ( 13 ) coupled to a duster ( 51 ) for dispensing the fill of particles, means for spreading the fill of particles within the main binder, electromagnetic means ( 60 ) for producing an anisotropic magnetic field for magnetizing the particles, a sprayer ( 80 ) for depositing an additional binder, dryer means ( 100 ), demagnetizer means ( 110 ), and winder means ( 120 ). The invention is applicable to media particularly in paper-making, games, decoration, or building.

Description

La présente invention se rapporte principalement à un enduit magnétique, à un procédé d'enduction de surfaces externes, notamment de matériaux en feuilles ou en rouleaux, avec un tel enduit, et à un appareil d'enduction mettant en oeuvre ledit procédé.The present invention relates mainly to a magnetic coating, to a process for coating external surfaces, in particular sheet materials or rolls, with such a coating, and to a coating apparatus implementing said method.

L'invention s'applique dans le domaine du jeu, notamment pour des puzzles, des jeux de société, des matériaux éducatifs ou didactiques, dans le domaine de la papeterie, de la décoration ou du bâtiment : revêtement mural, fixation amovible à l'aide d'éléments aimantés (magnet en terminologie anglo-saxonne), de signalisation ou de placage magnétique, revêtement de surfaces plâtrées, par exemple de surfaces en placoplâtre, ou blindage électromagnétique. L'invention s'applique également au domaine de la publicité, par exemple pour des affiches ou posters extérieurs et intérieurs.The invention applies in the field of play, especially for puzzles, board games, educational or didactic materials, in the field of stationery, decoration or building: wallcovering, removable attachment to the using magnetic elements (magnets in English terminology), signaling or magnetic veneer, coating plastered surfaces, for example plasterboard surfaces, or electromagnetic shielding. The invention also applies to the field of advertising, for example for outdoor and indoor posters or posters.

Il est connu, par exemple du document GB 1 444 858 A, de munir divers objets d'une surface aimantée pour permettre leur fixation provisoire sur un support ferromagnétique, telles que porte de réfrigérateur, porte blindée ou analogues. D'autre part, on a utilisé des plaques de fer comme supports de jeux contenant des pièces aimantées tels que les jeux d'échecs. Malheureusement, la plupart des surfaces comme les murs, les éléments en carton ou analogues ne sont pas capables de retenir des aimants. De même, on ne dispose pas de manière courante de supports magnétiques souples susceptibles d'être roulés ou pliés.It is known, for example from GB 1 444 858 A, to provide various objects with a magnetized surface to allow their temporary fixing on a ferromagnetic support, such as refrigerator door, armored door or the like. On the other hand, iron plates have been used as game supports containing magnetic pieces such as chess sets. Unfortunately, most surfaces such as walls, cardboard elements or the like are not able to hold magnets. Similarly, there is currently no flexible magnetic media that can be rolled or folded.

Il est connu du document NL 8 202 336 de réaliser une couche d'aimantation permanente avec des particules de poudre ferromagnétique dans un colorant. De telles couches ne permettent pas d'obtenir une bonne aimantation.It is known from NL 8 202 336 to provide a permanent magnetization layer with ferromagnetic powder particles in a dye. Such layers do not provide good magnetization.

La présente invention vise à pallier ces inconvénients, en proposant un enduit magnétique générant un milieu anisotrope permettant d'optimiser les forces d'attraction magnétique et de glissement exercées par l'enduit, cet enduit étant apte à être appliqué sur tout support, et notamment papier, carton, feuilles de matière plastique souple ou rigide, papier peint, murs et autres. Le rendement magnétique des forces exercées par les particules en milieu anisotrope est supérieur de 25 à 30% à celui obtenu en milieu isotrope.The present invention aims to overcome these disadvantages, by providing a magnetic coating generating an anisotropic medium for optimizing the magnetic attraction and sliding forces exerted by the coating, this coating being able to be applied to any support, and in particular paper, cardboard, sheets of material flexible or rigid plastic, wallpaper, walls and others. The magnetic efficiency of the forces exerted by the particles in anisotropic medium is 25 to 30% greater than that obtained in an isotropic medium.

Plus précisément, la présente invention a pour objet un enduit magnétique, susceptible d'être étalé sensiblement régulièrement sur une surface, dans lequel des particules conductrices orientées par une aimantation préalable selon un champ électromagnétique inducteur, notamment des particules ferromagnétiques telles que des particules d'oxyde de fer, sont noyées dans un liant.More precisely, the subject of the present invention is a magnetic coating capable of being spread out substantially regularly on a surface, in which conductive particles oriented by a prior magnetization according to an inductive electromagnetic field, in particular ferromagnetic particles such as particles of iron oxide, are embedded in a binder.

Dans une forme de réalisation particulière, l'enduit selon l'invention permet de réaliser un blindage électromagnétique en assurant d'une part le confinement des ondes électromagnétiques émises dans une pièce et, d'autre part, en limitant la pénétration d'ondes électromagnétiques dans cette pièce. Pour cette application notamment, des particules conductrices non ferromagnétiques, par exemple des particules de cuivre, sont additionnées ou substituées à des particules ferromagnétiques, et la colle utilisée comme liant principal est de préférence conductrice de l'électricité.In a particular embodiment, the coating according to the invention makes it possible to carry out an electromagnetic shielding by firstly ensuring the confinement of the electromagnetic waves emitted in a room and, secondly, by limiting the penetration of electromagnetic waves. in this piece. For this application in particular, non-ferromagnetic conductive particles, for example copper particles, are added to or substituted for ferromagnetic particles, and the adhesive used as the main binder is preferably electrically conductive.

Selon une caractéristique avantageuse, les particules conductrices sont en forme de bâtonnet afin d'augmenter leur capacité à s'orienter selon le champ électromagnétique inducteur.According to an advantageous characteristic, the conductive particles are rod-shaped in order to increase their ability to orient themselves according to the inductive electromagnetic field.

Selon des modes de réalisation avantageux dudit enduit, ledit liant est une résine adhésive, notamment une colle thermofusible (hotmelt en terminologie anglo-saxonne), une colle à froid ou une peinture. Afin d'éviter la formation de courants de Foucault, la résine adhésive est de préférence non-conductrice de l'électricité. On peut par exemple utiliser des colles en dispersion notamment acrylique, acétate de vinyle, copolymère acétate de vinyl-éthylène ou styrène acrylique, les colles en solution du type acétate de vinyle, acrylique ou styrène acrylique, des colles végétales notamment du type amidon, dextrine ou caséine ou, avantageusement des colles thermofusibles réalisées notamment sur une base éthylène acétate de vinyle, éthylène acrylique, polyoléfine, styrène butadiene ou styrène isoprène.According to advantageous embodiments of said coating, said binder is an adhesive resin, in particular a hot melt glue (hot melt in English terminology), a cold glue or a paint. In order to avoid the formation of eddy currents, the adhesive resin is preferably non-conductive of electricity. It is possible, for example, to use dispersing glues, especially acrylic, vinyl acetate, vinyl ethylene acetate copolymer or acrylic styrene, solution-type glues. vinyl acetate, acrylic or styrene acrylic, vegetable glues including starch, dextrin or casein or, advantageously hot melt glues made in particular on an ethylene vinyl acetate, ethylene acrylic, polyolefin, styrene butadiene or styrene isoprene basis.

La présente invention a également pour objet un procédé d'enduction d'un tel enduit sur un support dorsal, comportant une étape d'application d'un liant principal sur le support guidé par une bande transporteuse, une étape de distribution contrôlée et de répartition uniforme de la charge de particules conductrices dans la résine couplée à une étape d'orientation des particules par aimantation, suivie d'une étape de démagnétisation, d'une étape de recouvrement des particules par dépôt d'un liant complémentaire, et d'une étape de séchage de l'ensemble.The present invention also relates to a process for coating such a coating on a backing support, comprising a step of applying a main binder to the support guided by a conveyor belt, a controlled distribution and distribution step uniformity of the charge of conductive particles in the resin coupled to a step of orientation of the particles by magnetization, followed by a demagnetization step, a step of covering the particles by deposition of a complementary binder, and a drying step of the whole.

Dans le cas où les particules conductrices comprennent au moins en partie des particules ferromagnétiques, l'étape d'aimantation est suivie d'une étape de démagnétisation, afin de ne pas perturber les étapes ultérieures, et l'étape de séchage est suivie d'une étape de remagnétisation des particules.In the case where the conductive particles comprise at least partly ferromagnetic particles, the magnetization step is followed by a demagnetization step, so as not to disturb the subsequent steps, and the drying step is followed by a step of remagnetization of the particles.

Selon des modes particuliers de mise en oeuvre :

  • la distribution contrôlée et la répartition de la charge sont réalisées par programmation du débit de poudre délivré en fonction de la densité de particules choisie, puis par tamisage ou dosage uniforme sur le support préencollé ; une répartition aléatoire des particules permet d'obtenir une épaisseur contrôlée et uniforme de la surface supérieure ainsi formée ;
  • l'étape d'aimantation intervient une fois les particules effectivement réparties dans le liant principal consécutivement à l'étape de distribution et de répartition des particules, mais avant la prise effective par solidification du liant pour que les particules puissent s'orienter ;
  • les étapes de distribution, de répartition et d'aimantation des particules sont combinées de sorte que les particules sont orientées par aimantation avant leur répartition effective dans le liant.
According to particular modes of implementation:
  • the controlled distribution and the distribution of the charge are carried out by programming the delivered powder flow rate as a function of the density of particles chosen, then by sieving or uniform dosing on the pre-bonded support; a random distribution of the particles makes it possible to obtain a controlled and uniform thickness of the upper surface thus formed;
  • the magnetization step occurs once the particles are effectively distributed in the main binder after the particle distribution and distribution step, but before the effective setting solidification of the binder so that the particles can be oriented;
  • the steps of distribution, distribution and magnetization of the particles are combined so that the particles are oriented by magnetization before their effective distribution in the binder.

Une forme de réalisation avantageuse consiste à pulvériser une résine adhésive comme liant de recouvrement des particules et de contrecoller un support sur la surface supérieure ainsi formée pour servir de support frontal. Tout type de support peut être utilisé comme support frontal, à savoir : carton, papier, tissu, feuille de matière plastique souple ou rigide, etc., la nature du support frontal pouvant être identique ou différente de celle du support dorsal.An advantageous embodiment consists of spraying an adhesive resin as a binder for covering the particles and laminating a support on the upper surface thus formed to serve as a frontal support. Any type of support may be used as a front support, namely: cardboard, paper, fabric, flexible or rigid plastic sheet, etc., the nature of the front support may be identical or different from that of the back support.

Alternativement, dans le cas où l'utilisation d'un support frontal n'est pas envisagée afin de conserver l'aspect brut du support dorsal, l'étape de recouvrement peut avantageusement consister à pulvériser un vernis comme liant complémentaire.Alternatively, in the case where the use of a front support is not envisaged in order to preserve the raw appearance of the back support, the covering step may advantageously consist in spraying a varnish as a complementary binder.

L'invention a également pour objet un appareil d'enduction pour la mise en oeuvre du procédé selon l'invention, comportant des moyens d'alimentation du support, alimentation en continu ou discontinue selon que le support se présente en rouleau ou en feuilles, des moyens d'application d'un liant principal par rouleaux presseurs ou par au moins une buse, couplés à des moyens de chauffage, un réservoir de particules couplé à un saupoudreur pour la distribution de la charge de particules, des moyens répartiteurs de la charge de particules dans le liant principal, des moyens électromagnétiques de production d'un champ magnétique anisotrope d'aimantation des particules, un pulvérisateur pour déposer le liant complémentaire, et des moyens de séchage.The subject of the invention is also a coating apparatus for implementing the method according to the invention, comprising means for feeding the support, feeding continuously or discontinuously, depending on whether the support is in roll or in sheets, means for applying a main binder by pressure rollers or by at least one nozzle, coupled to heating means, a particle reservoir coupled to a sprinkler for distributing the charge of particles, means for distributing the charge particles in the main binder, electromagnetic means for producing an anisotropic magnetic particle magnetization field, a sprayer for depositing the complementary binder, and drying means.

Selon des exemples préférés, le saupoudreur est programmé pour délivrer la quantité de poudre correspondant à la densité de charge choisie, de préférence entre 100 et 900 g/m2 , les moyens d'application de liant délivrent de préférence de l'ordre 10 à 50 g/m2 de produit, les moyens répartiteurs sont constitués par un système de tamis vibrants ou par au moins un dosimètre, aptes à former des motifs particuliers par masquage, et les moyens électromagnétiques d'aimantation sont formés par un électroaimant.According to preferred examples, the sprinkler is programmed to deliver the quantity of powder corresponding to the charge density chosen, preferably between 100 and 900 g / m 2 , the binder application means preferably deliver from about 10 to 50 g / m 2 of product, the distribution means are constituted by a system of vibrating screens or by at least one dosimeter, able to form particular patterns by masking, and the electromagnetic magnetization means are formed by an electromagnet.

Selon des modes de réalisation avantageux dudit appareil :

  • un appareil de démagnétisation, disposé immédiatement en aval des moyens électromagnétiques d'aimantation, et un magnétiseur final, disposé en aval du tunnel de séchage, dans le cas où la charge comprend au moins partiellement des particules ferromagnétiques ;
  • lorsque l'alimentation est réalisée en continu, le support est alimenté par un rouleau débobineur, l'alimentation en support frontal est le cas échéant effectuée également par un rouleau débobineur couplé à des rouleaux presseurs sur la bande transporteuse, et un rouleau d'enroulage final fournit une bobine du produit obtenu par le procédé de l'invention ;
  • lorsque l'alimentation est réalisée en discontinu, le support est alimenté feuille à feuille sur la bande transporteuse à partir d'un bac d'alimentation, et l'alimentation en support frontal est le cas échéant effectuée également par un bac d'alimentation feuille à feuille, les bacs d'alimentation et les moyens de répartition de la charge de particules étant commandés par un système de distribution automatisée et réglée sur une cadence de défilement ; les moyens d'application du liant, et le cas échéant d'application du liant complémentaire, sont réglés par un contrôleur séquentiel optique à cellules photoélectriques, relié au système de distribution automatisée.
According to advantageous embodiments of said apparatus:
  • a demagnetizing apparatus, disposed immediately downstream of the electromagnetic magnetization means, and a final magnetizer, disposed downstream of the drying tunnel, in the case where the charge comprises at least partially ferromagnetic particles;
  • when the feed is carried out continuously, the support is fed by a uncoiler roll, the front support feed is optionally also performed by a de-unloading roller coupled to pressure rollers on the conveyor belt, and a winding roller final provides a coil of the product obtained by the method of the invention;
  • when the feed is carried out discontinuously, the support is fed sheet by sheet on the conveyor belt from a feed tray, and the front support feed is optionally also performed by a sheet feed tray sheet, the feed tanks and the particle load distribution means being controlled by an automated dispensing system and set at a scroll rate; the means for applying the binder, and, if appropriate, for applying the complementary binder, are set by a sequential controller photoelectric cell optics, connected to the automated distribution system.

La présente invention sera mieux comprise au moyen de la description ci-après et des figures annexées données à titre d'exemples non limitatifs et qui représentent :

  • la figure 1, une vue latérale schématisée d'un exemple d'appareil d'enduction en continu selon le procédé de l'invention ;
  • la figure 2, une vue latérale schématisée d'un exemple d'appareil d'enduction en discontinu selon le procédé de l'invention.
The present invention will be better understood by means of the description below and the appended figures given as non-limiting examples and which represent:
  • Figure 1 is a schematic side view of an example of continuous coating apparatus according to the method of the invention;
  • Figure 2 is a schematic side view of an example of a batch coating apparatus according to the method of the invention.

Sur la figure 1, l'appareil d'enduction représenté présente différents postes de travail en continu utilisés en combinaison, en alternance ou en option. L'appareil est un dispositif simple face étant bien entendu que les appareils double-face ne sortent pas du cadre de la présente invention. L'exemple non limitatif présenté décrit l'enduction d'un papier peint afin d'illustrer le fonctionnement de l'appareil.In Figure 1, the coating apparatus shown has different continuous work stations used in combination, alternately or optionally. The apparatus is a single-sided device, it being understood that double-sided devices are not outside the scope of the present invention. The non-limiting example presented describes the coating of a wallpaper to illustrate the operation of the apparatus.

L'appareil comporte un rouleau débobineur d'alimentation 10 d'un papier dorsal 11, entraîné en rotation par des moyens connus, le papier étant guidé sur une bande transporteuse continue 20 entraînée en translation à la même vitesse par des éléments rotatifs 21. La vitesse linéaire est comprise par exemple entre 20 et 250 m/min., de préférence entre 30 et 150 m/min.The apparatus comprises a backing roll for feeding a backing paper 11, rotated by known means, the paper being guided on a continuous conveyor belt 20 driven in translation at the same speed by rotary elements 21. linear speed is for example between 20 and 250 m / min., preferably between 30 and 150 m / min.

En regard de la bande 20, sont disposés des moyens d'application d'une colle thermofusible, sous la forme d'une buse à lèvres 30 couplée à des moyens de chauffage 31, et d'une machine à rouleaux presseurs 40 pour l'application d'une colle 12 à froid ou thermofusible. Les moyens d'application de liant délivrent de préférence de l'ordre 10 à 50 g/m2 de produit, de préférence environ 35g/m2. L'un ou l'autre de ces moyens de distribution de colle est utilisé suivant la nature de la colle.Opposite the strip 20 are means for applying a hot melt glue, in the form of a lip nozzle 30 coupled to heating means 31, and a press roll machine 40 for application of a glue 12 cold or hot melt. The binder application means preferably deliver about 10 to 50 g / m 2 of product, preferably about 35 g / m 2 . One or other of these glue distribution means is used depending on the nature of the glue.

La température de mise en oeuvre de colles thermofusibles, au moment de l'aimantation, doit être inférieure à la température de Curie du matériau ferromagnétique employé. Pour une colle de type hotmelt, la température d'application est comprise entre 140 et 190°C. Une machine de type à rouleau, comme par exemple une machine comportant un générateur 3960 Multiscan® vendu par la Société NORDSON connecté par des tuyaux chauffants automatiques à des pistolets automatiques commercialisés par cette Société sous la référence H20. La colle s'écoule entre deux rouleaux 40 et s'écoule par un espace calibré ménagé entre ces rouleaux.The temperature of implementation of hot melt glues, at the moment of magnetization, must be lower than the Curie temperature of the ferromagnetic material used. For a hotmelt type adhesive, the application temperature is between 140 and 190 ° C. A roller type machine, such as a machine comprising a 3960 Multiscan® generator sold by NORDSON Company connected by automatic heating pipes to automatic guns marketed by this company under the reference H20. The adhesive flows between two rollers 40 and flows through a calibrated space formed between these rollers.

Un réservoir 50 de particules 13 couplé à un saupoudreur 51 est ensuite prévu pour la distribution de particules ferromagnétiques en poudre. Le saupoudreur est programmé pour délivrer la quantité de poudre correspondant à la densité de charge choisie, le mélange d'un liant typiquement une peinture ou une colle avec des particules ferromagnétiques formant une charge dans le liant correspondant à 200 à 850 g au mètre carré d'oxyde de fer, de préférence sensiblement égal à 800 g au mètre carré d'oxyde de fer. Avantageusement, on utilise la quantité maximale de charge ferromagnétique susceptible d'être acceptée par le liant, par exemple six unités en poids de poudre ferromagnétique pour deux unités en poids de liant.A reservoir 50 of particles 13 coupled to a sprinkler 51 is then provided for the distribution of ferromagnetic particles in powder form. The sprinkler is programmed to deliver the quantity of powder corresponding to the chosen charge density, the mixture of a binder typically a paint or an adhesive with ferromagnetic particles forming a charge in the binder corresponding to 200 to 850 g per square meter. iron oxide, preferably substantially equal to 800 g per square meter of iron oxide. Advantageously, the maximum amount of ferromagnetic charge that can be accepted by the binder is used, for example six units by weight of ferromagnetic powder for two units by weight of binder.

Pour un matériau ne devant pas présenter de rémanence, tout matériau ferromagnétique susceptible de présenter la granulométrie désirée et la stabilité, notamment chimique, dans le temps peut être employé. On peut par exemple employer du fer doux, du fer trempé, de la ferrite, tout oxyde de fer, des terres rares ferromagnétiques, du samarium, du baryum ou du cobalt. En variante, on utilise des particules de fer recouvertes par un matériau de protection contre la corrosion, par exemple par une couche de cobalt. On peut également utiliser du chrome, de l'oxyde de chrome ainsi que les particules utilisées pour l'enduction de bandes magnétiques.For a material not having to exhibit remanence, any ferromagnetic material likely to have the desired particle size and stability, especially chemical, over time can be used. For example, soft iron, hardened iron, ferrite, any iron oxide, ferromagnetic rare earths, samarium, barium or cobalt may be used. Alternatively, coated iron particles are used by a protective material against corrosion, for example by a layer of cobalt. It is also possible to use chromium, chromium oxide and the particles used for coating magnetic tapes.

Les particules d'oxyde de fer utilisées ont la forme de bâtonnets allongés et présente une faible granularité de manière à obtenir un état de surface lisse. D'excellents résultats ont été obtenus avec de l'oxyde de fer dont la granulométrie était égale à 24 µm, les granulométries inférieures convenant également. Si l'état de surface granuleux est acceptable, on peut utiliser des granulométries supérieures, par exemple comprises entre 25 et 300 µm.The iron oxide particles used are in the form of elongate rods and have a low granularity so as to obtain a smooth surface state. Excellent results were obtained with iron oxide whose particle size was equal to 24 microns, the lower particle sizes also being suitable. If the granular surface condition is acceptable, it is possible to use larger particle sizes, for example between 25 and 300 μm.

Un système de tamis vibrants (non représenté) est couplé au saupoudreur 51 pour répartir uniformément les particules sur le papier dorsal préencollé. En variante, un dosimètre programmable peut être utilisé pour adapter la quantité de poudre à déposer. Ce dépôt peut être effectué avec des motifs prédéterminés par masquage à l'aide d'écrans prédécoupés.A vibrating screen system (not shown) is coupled to the sprinkler 51 to evenly distribute the particles on the backed-up backing paper. Alternatively, a programmable dosimeter may be used to adjust the amount of powder to be deposited. This deposit can be performed with predetermined patterns by masking using pre-cut screens.

Un champ magnétique induit par un électroaimant 60 est créé afin d'orienter par aimantation les particules juste déposées dans la résine adhésive, c'est-à-dire avant la solidification de la colle. L'utilisation d'une colle thermofusible dans l'exemple de mise en oeuvre est particulièrement avantageuse car on peut en contrôler aisément l'ouverture et la fermeture. Alternativement le champ magnétique est formé entre le saupoudreur et les moyens répartiteurs. Cette solution est avantageuse lorsqu'il se produit, selon la nature de poudre utilisée, un phénomène de " méchage " pouvant nuire à la régularité de dépose sur le papier.A magnetic field induced by an electromagnet 60 is created in order to orient by magnetization the particles just deposited in the adhesive resin, that is to say before the solidification of the adhesive. The use of a hot melt glue in the exemplary embodiment is particularly advantageous because it can easily control the opening and closing. Alternatively, the magnetic field is formed between the sprinkler and the distribution means. This solution is advantageous when, depending on the nature of the powder used, a phenomenon of "wicking" may affect the regularity of deposit on the paper.

L'aimantation est effectuée en polarisant magnétiquement les particules. Le papier enduit passe dans l'entrefer de l'électroaimant 60 générant un champ magnétique sensiblement uniforme sur toute la largeur du papier On utilise par exemple un électroaimant engendrant un champ magnétique intense sensible ment égal à 0,5 Teslas. Il est à noter que la viscosité du revêtement selon la présente invention ainsi que l'amplitude du champ magnétique sont tels que la migration des particules magnétiques en dehors du liant et leur collage dans l'entrefer de l'électroaimant est soigneusement évité. De même, des moyens de guidage (non représentés) empêchent le papier recouvert du revêtement selon la présente invention de venir se coller à l'un des pôles de l'aimant, dans le cas de l'utilisation d'un aimant permanent.The magnetization is carried out by magnetically polarizing the particles. The coated paper passes into the gap of the electromagnet 60 generating a field Magnetic substantially uniform over the entire width of the paper is used for example an electromagnet generating an intense magnetic field substantially equal to 0.5 Tesla. It should be noted that the viscosity of the coating according to the present invention as well as the amplitude of the magnetic field are such that the migration of the magnetic particles outside the binder and their bonding in the gap of the electromagnet is carefully avoided. Likewise, guiding means (not shown) prevent the coated paper of the coating according to the present invention from sticking to one of the poles of the magnet, in the case of the use of a permanent magnet.

Le papier enduit passe ensuite sous un appareil de démagnétisation 70, disposé immédiatement en aval des moyens électromagnétiques d'aimantation.The coated paper then passes under a degaussing apparatus 70, disposed immediately downstream of the electromagnetic magnetization means.

Si l'enduit formé de la résine chargée de particules doit être apparent sur le papier, l'utilisation d'une peinture comme liant peut être avantageuse pour fournir une couleur désirée. Mais les particules ferromagnétiques peuvent modifier la couleur de la peinture. Si cet effet n'est pas désiré, il est possible de la recouvrir ensuite par une ou plusieurs couches de peinture dépourvue(s) de charge ferromagnétique. Un pulvérisateur 80 dépose alors le liant complémentaire. Le débit de ce pulvérisateur est réglé pour que toutes les particules soient noyées dans ce liant. Ce liant peut également être un vernis, par exemple translucide si l'on désire conserver en fond la vue du papier dorsal.If the coating formed of the particle-laden resin is to be apparent on the paper, the use of a paint as a binder may be advantageous in providing a desired color. But ferromagnetic particles can change the color of the paint. If this effect is not desired, it can be covered by one or more layers of paint free of ferromagnetic charge. A sprayer 80 then deposits the complementary binder. The flow rate of this sprayer is adjusted so that all the particles are embedded in this binder. This binder can also be a varnish, for example translucent if it is desired to keep the bottom view of the back paper.

Un support frontal en papier est ensuite à déposer dans cet exemple, et le pulvérisateur 80 délivre dans ce cas une colle comme liant complémentaire. L'alimentation en support frontal 14 est effectuée également par un rouleau débobineur 90 couplé à des rouleaux presseurs 91 sur la bande transporteuse.A front paper support is then to be deposited in this example, and the sprayer 80 delivers in this case a glue as a complementary binder. The front support feed 14 is also performed by a uncoiler roll 90 coupled to pressure rollers 91 on the conveyor belt.

Un tunnel de séchage 100, alternativement des rouleaux chauffants, et un magnétiseur final 110, disposé en aval du tunnel de séchage, sont prévus. Le magnétiseur est un tambour couplé en rotation à la bande transporteuse, alternant des pôles sud et nord selon un pas magnétique préalablement calculé. La vitesse de défilement et de magnétisation est de l'ordre de 80 m/min. La tension appliquée est de l'ordre de 2000 à 3000 V, délivrant un champ de 8000 à 9000 gauss, pour des laizes de papier comprises entre 700 et 1400 mm.A drying tunnel 100, alternately heating rollers, and a final magnetizer 110, arranged downstream of the drying tunnel, are provided. The magnetizer is a drum coupled in rotation to the conveyor belt, alternating south and north poles according to a previously calculated magnetic pitch. The speed of scrolling and magnetization is of the order of 80 m / min. The applied voltage is of the order of 2000 to 3000 V, delivering a field of 8000 to 9000 gauss, for paper widths between 700 and 1400 mm.

Un rouleau d'enroulage final 120 fournit une bobine du produit obtenu par le procédé de l'invention.A final winding roll 120 provides a roll of the product obtained by the process of the invention.

Pour obtenir un blindage au rayonnement électromagnétique, il est avantageux d'assurer une charge suffisante en particules ferromagnétiques pour rendre le revêtement selon la présente invention conducteur, au moins aux fréquences que l'on veut éliminer. En variante, on utilise des particules conductrices non ferromagnétiques, par exemple en cuivre, en complément ou à la place des particules ferromagnétiques pour former un blindage ou une cage de Faraday. Un tel blindage permet de protéger des équipements électroniques, notamment des équipements de télécommunications et des équipements informatiques, des perturbations extérieures ainsi que des indiscrétions en empêchant l'écoute des signaux électromagnétiques émis par ce type d'équipements en fonctionnement.In order to obtain an electromagnetic radiation shield, it is advantageous to ensure a sufficient charge of ferromagnetic particles to make the coating according to the present invention conductive, at least at the frequencies that it is desired to eliminate. Alternatively, non-ferromagnetic conductive particles, for example copper, are used in addition to or in place of the ferromagnetic particles to form a shield or a Faraday cage. Such shielding can protect electronic equipment, including telecommunications equipment and computer equipment, external disturbances and indiscretions by preventing the listening of electromagnetic signals emitted by this type of equipment in operation.

Sur la figure 2, l'appareil d'enduction, en variante de type alimentation en discontinu, présente également différents postes de travail utilisés en combinaison, en alternance ou en option.In FIG. 2, the coating apparatus, alternatively of the batch feed type, also has different workstations used in combination, alternately or optionally.

Le papier est alimenté feuille à feuille 21 sur la bande transporteuse 20 à partir d'un bac d'alimentation 15, et l'alimentation en support dorsal 24 est effectuée également par un bac d'alimentation feuille à feuille 16 couplé à des cylindres presseurs 17. Les bacs d'alimentation et les moyens de répartition de la charge de particules, identiques à ceux décrits précédemment, sont commandés par un système de distribution automatisée (non représenté) connu de l'homme de l'art et réglée sur une cadence de défilement. L'appareil encolle par exemple 90 cartons à la minute, chaque carton ayant une surface de 40 cm sur 55 cm.The paper is fed sheet-by-sheet 21 on the conveyor belt 20 from a feed tray 15, and the back-up feed 24 is also performed by a sheet-fed feed tray 16 coupled with pressing rolls. 17. The feed tanks and the particle charge distribution means, identical to those described above, are controlled by an automated dispensing system (not shown) known to those skilled in the art and set at a scroll rate. The device glues for example 90 cartons per minute, each carton having a surface of 40 cm by 55 cm.

Les moyens d'application du liant, 30 et 40, et du liant complémentaire 80, identiques à ceux décrits précédemment, sont réglés par un contrôleur séquentiel optique à cellules photoélectriques 25, relié au système de distribution automatisée.The binder application means, 30 and 40, and the complementary binder 80, identical to those described above, are set by an optical photocell sequential controller 25, connected to the automated distribution system.

Dans cet exemple de réalisation, le magnétiseur final 111 se présente sous la forme d'un électroaimant et le système de stockage se présente sous la forme d'un bac 121 apte à empiler les feuilles enduites par l'appareil selon l'invention, par exemple des feuilles de papier décorées ou non, du carton, des plaques plastiques ou analogues.In this embodiment, the final magnetizer 111 is in the form of an electromagnet and the storage system is in the form of a tray 121 capable of stacking the sheets coated by the apparatus according to the invention, by examples of paper sheets decorated or not, cardboard, plastic plates or the like.

L'invention n'est pas limitée aux exemples de réalisation décrits et représentés. Le procédé selon l'invention permet également d'adapter l'épaisseur de l'enduit en fonction du grammage des deux feuilles à encoller. Par exemple, le contrecollage d'une feuille d'un poids de 90 g sur une feuille de même épaisseur ou plus épaisse nécessite environ 90 à 120 g d'enduit. L'enduit magnétisé de l'aimant peut également être adapté dans les mêmes conditions. Autrement dit, l'épaisseur de l'enduit peut être parfaitement adaptée à l'effet esthétique, de poids, de force d'aimantation et de coût économique que l'on souhaite donner.The invention is not limited to the embodiments described and shown. The method according to the invention also makes it possible to adapt the thickness of the coating according to the basis weight of the two sheets to be glued. For example, laminating a sheet weighing 90 g on a sheet of the same thickness or thicker requires about 90 to 120 g of coating. The magnetized coating of the magnet can also be adapted under the same conditions. In other words, the thickness of the coating can be perfectly adapted to the aesthetic effect, weight, magnetization force and economic cost that it is desired to give.

Il est également possible, notamment dans le cas d'encollage discontinu, de déposer le revêtement sur uniquement des zones prédéfinies ou de magnétiser uniquement certaines zones de manière à faire tenir les aimants uniquement dans ces zones prédéfinies recevant en outre un marquage particulier correspondant par exemple à des réponses correctes à des questions imprimées sur la face visible du support. La magnétisation par zone peut être obtenue par des entrefers d'aimant ayant la forme des zones désirées soit en employant un ensemble d'électroaimants disposés de manière matricielle et en alimentant uniquementIt is also possible, especially in the case of discontinuous sizing, to deposit the coating on only predefined zones or to magnetize only certain zones so as to hold the magnets only in these predefined zones receiving in in addition to a particular marking corresponding for example to correct answers to questions printed on the visible side of the support. Zone magnetization can be achieved by magnet gaps having the shape of the desired areas either by employing a set of electromagnets arranged in a matrix manner and feeding only

Il est également possible de recouvrir les deux faces d'un support, typiquement d'un carton ou d'une feuille de plastique, avec le revêtement selon la présente invention de manière à permettre l'empilement des pièces. En variante, une première face du support reçoit un revêtement non aimanté, la face opposée recevant un revêtement susceptible d'être aimanté. Dans une deuxième variante de réalisation, les deux faces reçoivent un revêtement qui est par la suite aimanté de manière permanente.It is also possible to cover both sides of a support, typically a cardboard or a plastic sheet, with the coating according to the present invention so as to allow the stacking of parts. Alternatively, a first face of the support receives a non-magnetic coating, the opposite face receiving a coating capable of being magnetized. In a second variant embodiment, the two faces receive a coating which is thereafter permanently magnetized.

Par ailleurs, l'appareil selon l'invention comporte avantageusement des moyens de découpe du support enduit, par exemple pour former des éléments de type " magnet " (aimant en terminologie anglo-saxonne) comportant, après découpe, une portion de support relatif à un sujet ou adapté à recevoir, par exemple par collage, un autre support relatif à ce sujet. Dans cette application, les magnets obtenus sont maintenus sur toute surface métallique, par exemple porte de réfrigérateur ou toute surface (papier, carton, etc.) recouverte d'un enduit métallique (enduit contenant du métal en poudre en limaille ou autre) ou intégrant une surface totalement ou partiellement métallique (en bande, en grille ou autre), par l'exercice des forces magnétiques créées entre ces magnets et ladite surface métallique.Furthermore, the apparatus according to the invention advantageously comprises means for cutting the coated support, for example to form "magnet" type elements (magnet in English terminology) comprising, after cutting, a support portion relative to a subject or adapted to receive, for example by gluing, another support relating to this subject. In this application, the magnets obtained are held on any metal surface, for example a refrigerator door or any surface (paper, cardboard, etc.) covered with a metal coating (coating containing metal powder in filings or other) or integrating a totally or partially metallic surface (strip, grid or other), by the exercise of the magnetic forces created between these magnets and said metal surface.

Claims (21)

  1. A magnetic coating suitable for being spread substantially regularly over a surface (11), said coating being characterized in that it comprises a binder (12) having embedded therein conductive particles (13) directed by prior magnetization along an inductive electromagnetic field thereby generating an anisotropic medium.
  2. A magnetic coating according to claim 1, in which the conductive particles (13) comprise ferromagnetic particles such as iron oxide particles.
  3. A magnetic coating according to claim 1, in which the conductive particles comprise at least some particles that are not ferromagnetic particles, such as particles of copper in order to provide electromagnetic shielding.
  4. A magnetic coating according to any preceding claim, in which the conductive particles (13) are rod shaped.
  5. A magnetic coating according to any preceding claim, in which said binder is selected from a hot-melt adhesive resin, a cold glue, and a paint.
  6. A magnetic coating according to the preceding claim, in which the adhesive resin is preferably not electrically conductive.
  7. A method of applying a coating on a backing medium (11), the method comprising a step of applying a main binder (12) on the medium while the medium is being guided by a conveyor (20), a step of controlled dispensing and uniform spreading of a filler of conductive particles (13) in the binder, coupled with a step of directing the particles by magnetization, followed by a step of demagnetization, a step of covering the particles in a deposit of an additional binder, and a step of drying the whole.
  8. A method of applying a coating on a backing medium according to claim 7, characterized in that when the filler of conductive particles comprises at least partially ferromagnetic particles, the magnetization step is followed by a step of demagnetization, and the drying step is followed by a step of remagnetizing the particles.
  9. A method of applying a coating on a backing medium according to claim 7 or claim 8, in which the controlled dispensing of the filler is performed by programming the powder delivery rate as a function of the density selected for particles, and then by uniform spreading over the preglued medium.
  10. A method of applying a coating on a backing medium according to claim 9, in which the magnetization step occurs after the particles have indeed been spread within the main binder following the step of dispensing and spreading the particles, but prior to the binder actually setting by solidifying.
  11. A method of applying a coating on a backing medium according to claim 9, in which the steps of dispensing, of spreading, and of magnetizing the particles are combined in such a manner that the particles are directed by magnetization prior to being actually spread within the binder.
  12. A method of applying a coating on a backing medium according to any one of claims 7 to 11, in which an adhesive resin is sprayed as an additional binder covering the particles and to enable a medium (14) to be laminated onto the top surface to serve as a front medium.
  13. A method of applying a coating on a backing medium according to any one of claims 7 to 11, in which the covering step consists in spraying a varnish as the additional binder.
  14. Coating apparatus for implementing the method of the invention, the apparatus comprising means (10, 15) for feeding the medium (11, 21) onto a conveyor (20), means for applying a principal binder (12) via presser rollers (40) and via at least one nozzle (30), said means being coupled to heater means, a tank (50) of particles (13) coupled to a duster (51) for dispensing the filler of particles, means for spreading the filler of particles within the main binder, electromagnetic means (60) for producing an anisotropic magnetic field for magnetizing the particles, a spray (80) for depositing an additional binder, and dryer means (100).
  15. Coating apparatus according to claim 14, in which the duster (51) is programmed to deliver the quantity of powder that corresponds to the density selected for the filler, the spreader means are constituted by a system of vibrating screens, and the electromagnetic magnetization means are formed by an electromagnet (60).
  16. Coating apparatus according to claim 15, in which the spreader means are constituted by at least one measuring-out unit replacing the system of vibrating screens, the unit and the screens forming particular patterns by masking.
  17. Coating apparatus according to any one of claims 14 to 16, in which a demagnetizer (70) is placed immediately downstream from the electromagnetic magnetizing means (60) and a final magnetizer (110) is placed downstream from the dryer means (100), when the filler comprises at least partially ferromagnetic particles.
  18. Coating apparatus according to any one of claims 14 to 17, in which, when feeding is performed continuously, the medium is fed from a winding-off roll (10), the front medium (14) is fed from a winding-off roll (90) coupled to presser rollers (91) pressing on the conveyor (20), and a final winding roll (120) provides a reel of the resulting coated medium.
  19. Coating apparatus according to any one of claims 14 to 17, in which, when feeding is performed discontinuously, the backing medium (24) is fed sheet by sheet onto the conveyor from a feeder bin (15), and the front medium is fed likewise from a sheet by sheet feeder bin (16), the feeder bins and the means for spreading the filler of particles being controlled by a dispenser system that is automatic and adjusted to the rate of throughput.
  20. Coating apparatus according to claim 19, in which the means (30, 40) for applying the binder and the means (80) for applying the additional binder are governed by an optical sequential controller having photoelectric cells, and connected to the automatic dispenser system.
  21. apparatus according to any one of claims 14 to 20, in which means are provided for cutting up the resulting coated medium in order to form elements that are to be held in place on metal surfaces by magnetic forces acting between the element and the metal surface.
EP00949523A 1999-06-15 2000-06-09 Magnetic coating, coating method with same and coating apparatus therefor Expired - Lifetime EP1185989B1 (en)

Applications Claiming Priority (3)

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FR9907589 1999-06-15
FR9907589A FR2795223B1 (en) 1999-06-15 1999-06-15 MAGNETIC COATING, PROCESS FOR COATING SUCH A COATING AND COATING APPARATUS FOR IMPLEMENTING SAME
PCT/FR2000/001604 WO2000077803A1 (en) 1999-06-15 2000-06-09 Magnetic coating, coating method with same and coating apparatus therefor

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EP1185989B1 true EP1185989B1 (en) 2006-03-01

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US9724894B2 (en) * 2008-11-06 2017-08-08 Deetz Family, Llc Magnetic receptive extruded films
JP5614135B2 (en) * 2010-07-06 2014-10-29 デクセリアルズ株式会社 Anisotropic conductive adhesive, manufacturing method thereof, connection structure and manufacturing method thereof
BR112013010024A2 (en) 2010-10-27 2016-08-02 Kraft Foods Global Brands Llc packaging to accommodate product which can be magnetically closed
US20140213971A1 (en) 2011-04-27 2014-07-31 Mark J. Dolan Nerve impingement systems including an intravascular prosthesis and an extravascular prosthesis and associated systems and methods
US20170037568A1 (en) 2015-08-05 2017-02-09 Milliken & Company Installation of Multi-Component Floor Mat
US20180055266A1 (en) 2016-08-24 2018-03-01 Milliken & Company Floor Mat with Hidden Base Component
CN108251820A (en) * 2018-03-09 2018-07-06 无锡博硕珈睿科技有限公司 The manufacturing method and manufacturing equipment of self-heating product/material
KR102560966B1 (en) * 2021-10-08 2023-07-28 주식회사 위츠 Method of manufaturing wireless charging module coated with magnetic material on the coil surface
US20230116340A1 (en) * 2021-10-08 2023-04-13 Wits Co., Ltd. Method of manufacturing wireless charging coil module coated with magnetic material on surface of coil
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JP2003503512A (en) 2003-01-28
EP1185989A1 (en) 2002-03-13
CA2376774A1 (en) 2000-12-21
WO2000077803A1 (en) 2000-12-21
ATE319173T1 (en) 2006-03-15
FR2795223A1 (en) 2000-12-22
FR2795223B1 (en) 2003-02-07
US7001645B1 (en) 2006-02-21
AU6285500A (en) 2001-01-02
DE60026314D1 (en) 2006-04-27

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