EP1413649A1 - Enamelled watch dial and process for making it - Google Patents

Enamelled watch dial and process for making it Download PDF

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Publication number
EP1413649A1
EP1413649A1 EP02405902A EP02405902A EP1413649A1 EP 1413649 A1 EP1413649 A1 EP 1413649A1 EP 02405902 A EP02405902 A EP 02405902A EP 02405902 A EP02405902 A EP 02405902A EP 1413649 A1 EP1413649 A1 EP 1413649A1
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EP
European Patent Office
Prior art keywords
enamel
substrate
thickness
dial
white
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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EP02405902A
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German (de)
French (fr)
Inventor
Carlos Dias
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Manufacture Roger Dubuis SA
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Manufacture Roger Dubuis SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Manufacture Roger Dubuis SA filed Critical Manufacture Roger Dubuis SA
Priority to EP02405902A priority Critical patent/EP1413649A1/en
Priority to AU2003269661A priority patent/AU2003269661A1/en
Priority to AT03750226T priority patent/ATE405691T1/en
Priority to EP03750226A priority patent/EP1554415B1/en
Priority to DE60323117T priority patent/DE60323117D1/en
Priority to PCT/CH2003/000678 priority patent/WO2004038066A2/en
Publication of EP1413649A1 publication Critical patent/EP1413649A1/en
Priority to HK05106355.1A priority patent/HK1074062A1/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B19/00—Indicating the time by visual means
    • G04B19/06—Dials
    • G04B19/12—Selection of materials for dials or graduations markings
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23D—ENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS
    • C23D5/00—Coating with enamels or vitreous layers
    • C23D5/06—Coating with enamels or vitreous layers producing designs or letters

Definitions

  • the present invention relates to an enamel dial for a watch, as well as to a method for manufacturing an enamel dial.
  • Enamel dials have been known for a very long time in the field of watches and clocks. Such dials have been used more particularly for clocks, clocks and for pocket watches. All these dials are round in shape and the enamel is generally deposited on a copper substrate, flat or curved.
  • the enamel dials of non-circular shape pose problems of adhesion and difference in coefficient of expansion between the substrate and the white enamel.
  • a finishing flux which is a layer of transparent enamel
  • cracks can occur in the finishing flux, especially in curved areas of the dial shape, due to the too low hardness of the white enamel which behaves like a moving element.
  • the fondant layer does not adhere to white enamel.
  • the painted coating deposited on the white enamel layer also poses a problem of deformation of the painted lines. This distortion problem is particularly apparent when letters or numbers are painted, especially when it comes to Roman numerals, consisting of straight lines.
  • the object of the present invention is to solve the above problems in order to be able to remedy the faults found on non-circular enamel dials for watches, more particularly for wristwatches.
  • the present invention firstly relates to an enamel dial for watches according to claim 1. It also relates to a method of manufacturing an enamel dial for watches, of non-circular shape according to claim 5.
  • the substrate used in these examples is mild steel with a very low carbon content, less than 0.08% and preferably 0.004%. These are cold-rolled sheets for vitrification glazing.
  • the steels used are designated DC03ED or DC04ED according to European standard EN 10027-1.
  • Degreasing can be done either by burning, by treatment with hydrocarbons, or by alkaline degreasing, followed by several rinses. This operation is followed by pickling with dilute sulfuric acid (60 to 90g of concentrated acid with a density of 1.84 / l of water), for ten minutes at a temperature above 70 ° C, immediately followed by neutralization in a slightly alkaline bath at 0.3-0.5% Na 2 O at 65-80 ° C, then drying with hot air.
  • dilute sulfuric acid 60 to 90g of concentrated acid with a density of 1.84 / l of water
  • the substrate thus prepared is then ready to receive a layer of mass enamel which on the one hand constitutes an agent of adhesion between the support and the white enamel covering which will be deposited later, on the other hand makes it possible to balance the expansions between the substrate and the white enamel covering.
  • This mass enamel layer also makes it possible to absorb the gases which emanate from the sheet during cooking.
  • the mass enamel used in the following examples has the following composition, expressed in g: Hard frit 40 20 20 Medium frit 40 40 30 Soft frit 20 40 50 Quartz 10 Clay 6 bentonite 0.25 Sodium nitrite 0.10 Borax 0.50 Magnesium carbonate 0.15 Water 50 to 55
  • the enamel slip prepared using this composition is ground until the desired fineness and density are obtained, determined experimentally, it being understood that too great a fineness increases the surface tension of the enamel and may cause withdrawal. Then it is passed through a magnetic separator to remove the ferrous particles.
  • the mass enamel layer is deposited on the entire substrate (front, back and edge) using a spray gun, followed by drying intended to remove the water before the enamel is cooked. mass. All the usual drying methods can be used, in the open air, in an oven or by radiation.
  • the mass enamel is fired in an electric box oven heated between 760 ° and 860 ° C so as to obtain a uniform coating.
  • the preparation of white enamel is made from commercial products available in powder form or in pieces. In either case, this product must be ground to obtain a fine powder with regular grains, the size of which is around 10 to 15 ⁇ m.
  • the grinding is preferably carried out in an agate grinder. Distilled water is added to the powder and the grinding is interspersed with several washes to remove the impurities and the silt formed by the finest particles of enamel which remain in suspension in the water.
  • the enamel obtained is then acidified using nitric acid diluted to 40% (60% acid in 40% water) to dissolve the non-assimilated metallic elements within the enamel, the various salts derived enamel during grinding (silt) and to dissolve organic matter which may be in suspension in water.
  • Another effect of the acidification of the enamel is to harden it. This hardening is directly linked to the proportion of acid introduced into the enamel slip, which makes it possible to adjust the hardness of the enamel layer, as will be explained below.
  • the good hardness of the white enamel is the condition so that the finishing fondant layer does not crack, in particular at the level of the curve.
  • the tests carried out have shown that the hardness of the white enamel must be between 5 and 6, preferably around 5.5, on the Mohs scale, used to measure the hardness of mineral materials.
  • the good hardness of the white enamel is the condition so that the lines painted on its surface do not deform.
  • the hardness measurement on the Mohs scale is a rough measurement, lacking in sensitivity in the case of the present invention.
  • this hardness is adjusted based on the deformation of the paint lines on its surface, as well as on the absence of cracking of the finishing fondant layer, that is to say - say according to the result obtained.
  • the adjustment of this hardness varies from one enamel to another and can only be determined empirically. However, for the same enamel, this adjustment is perfectly reproducible.
  • the enamel Once the enamel has been ground to the desired particle size and acidified, it is stored in airtight containers. Part of the enamel is wetted with distilled water, the other part is dried. The wet enamel is applied with a brush and then dried before being baked between 700 ° and 790 ° in an oven box. It is then slowly cooled and then degreased with industrial alcohol.
  • a second layer of dried enamel is then applied, using a very fine sieve, and a second firing is carried out. Finally, apply a new layer of dried enamel followed by firing. When the enamel is cold, it is degreased and ironed in the oven to even out the three layers.
  • the enamel is then stoned with 15 ⁇ - 9 ⁇ sandpaper and water to avoid overheating, until a regular desired thickness is obtained over the entire surface of the dial.
  • the final equalization is carried out after a further degreasing with alcohol, by ironing the dial in the oven between 700 ° and 790 ° C.
  • the frosted enamel during stoning becomes vitrified and tightened. This can be repeated if necessary.
  • the thickness of the dial is at most 1.1 mm, including the thickness of the substrate, that of the mass enamel covering the two faces of the substrate and that of the white enamel.
  • the next step is to deposit the paint.
  • This painting includes the numbers and the characters intended to indicate the hours, the minutes and various indications relating in particular to the mark.
  • This paint can also be decorative and include several colors, using the usual vitrifiable paints sold for enamel and which generally consist of metallic oxide pigments which are mixed with a fatty essence or another suitable dispersion medium. , in a proportion depending on the desired consistency.
  • vitrifiable colors are ground very finely and are applied with a brush to the white enamel, then they are fired between 750 ° C and 830 ° C, which has the effect of vitrifying the colors and embedding them in the white enamel.
  • the last step is to apply the finishing fondant.
  • This fondant is prepared by alternating grinding and washing as for white enamel without the addition of nitric acid, for approximately 35 minutes. The purpose of this operation is to improve the transparency of the fondant finish. When sufficiently ground and washed, the finishing fondant is dried.
  • the total thickness of the finishing fondant layer is of the order of 0.1 mm.
  • the paint adapts perfectly to the texture of the white background and the finishing flux does not crack during stoning.

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  • Chemical & Material Sciences (AREA)
  • Metallurgy (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Glass Compositions (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Physical Vapour Deposition (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Magnetic Heads (AREA)

Abstract

The dial has a non-circular shaped substrate made of decarbonized steel whose thickness is about 0.45 millimeter. Front and back sides of the substrate are covered with an adhesive agent and a thickness of white enamel extends in the front side. The agent is mass enamel and a part of the white enamel is covered with decoration or painted inscriptions. A thickness of flux of completion covers the white enamel and inscriptions. An Independent claim is also included for a manufacturing process of an enamel dial for a watch of non circular form.

Description

La présente invention se rapporte à un cadran émail pour montre, ainsi qu'à un procédé de fabrication d'un cadran émail.The present invention relates to an enamel dial for a watch, as well as to a method for manufacturing an enamel dial.

On connaît depuis très longtemps les cadrans émail dans le domaine de l'horlogerie et de la pendulerie. De tels cadrans ont été utilisés plus particulièrement pour les pendules, pendulettes et pour les montres de poches. Tous ces cadrans sont de forme ronde et l'émail est déposé généralement sur un substrat en cuivre, plat ou bombé.Enamel dials have been known for a very long time in the field of watches and clocks. Such dials have been used more particularly for clocks, clocks and for pocket watches. All these dials are round in shape and the enamel is generally deposited on a copper substrate, flat or curved.

L'apparition de la montre bracelet et celle de nouvelles techniques de fabrication des cadrans de montres ont coïncidé avec la disparition de ce type de cadrans, qui n'ont survécus essentiellement que dans le domaine des pendules et des montres de poches. Il n'en demeure pas moins que les cadrans émail présentent des caractéristiques intéressantes, dans la mesure où ils sont pratiquement inaltérables et permettent de recevoir des décors peints avec une palette de couleurs extrêmement vives et riches contenant des pigments d'oxydes métalliques.The appearance of the wristwatch and that of new techniques for manufacturing watch dials coincided with the disappearance of this type of dials, which essentially survived only in the field of pendulums and pocket watches. The fact remains that the enamel dials have interesting characteristics, insofar as they are practically unalterable and make it possible to receive decorations painted with an extremely vivid and rich palette of colors containing metallic oxide pigments.

Ce type de cadrans associe donc une durée de vie pratiquement indéfinie sans subir d'altération et permet aussi de conférer un aspect bien particulier à la montre, notamment sur le plan du décor. Toutefois, il est apparu que ces cadrans ne pouvaient être produits avec les techniques classiques que pour des cadrans ronds. En effet, les cadrans de toute autre forme, carrés, rectangulaires, polygonaux en particulier, subissent au cours des cuissons successives, des déformations dues aux déséquilibres des tensions qui s'exercent sur le substrat au cours des cuissons et refroidissements répétés et qui proviennent de sa forme non circulaire. Ceci est sans doute une des raisons pour lesquelles on ne connaît pas de cadran de montre émail de forme autre que ronde, l'autre raison venant du fait que les cadrans émail étaient principalement, voire exclusivement, destinés aux montres de poches qui étaient généralement rondes. De plus, ce problème de la déformation s'aggrave encore lorsque le cadran de forme non circulaire est galbé, ce qui a pour effet d'augmenter encore les possibilités de déformation.This type of dial therefore combines a practically indefinite lifespan without undergoing alteration and also makes it possible to impart a very particular aspect to the watch, in particular in terms of decoration. However, it appeared that these dials could only be produced with conventional techniques for round dials. Indeed, dials of any other shape, square, rectangular, polygonal in particular, undergo during successive baking, deformations due to imbalances in the tensions which are exerted on the substrate during baking and repeated cooling and which come from its non-circular shape. This is undoubtedly one of the reasons why we do not know an enamel watch dial of a shape other than round, the other reason coming from the fact that the enamel dials were mainly, if not exclusively, intended for pocket watches which were generally round . In addition, this problem of deformation becomes even worse when the non-circular dial is curved, which has the effect of further increasing the possibilities of deformation.

Outre le problème de la déformation du substrat, les cadrans émail de forme non circulaire, posent des problèmes d'adhérence et de différence de coefficient de dilatation entre le substrat et l'émail blanc. De plus, lorsque l'émail blanc et la peinture qui le recouvre au moins partiellement sont protégés par un fondant de finition, qui est une couche d'émail transparent, des fissures peuvent se produire dans la couche de fondant de finition, surtout dans les zones galbées du cadran de forme, due à la trop faible dureté de l'émail blanc qui se comporte comme un élément mouvant. Pour cette même raison la couche de fondant n'adhère pas à l'émail blanc. Le revêtement peint déposé sur la couche d'émail blanc pose également un problème de déformation des traits peints. Ce problème de déformation est particulièrement apparent lorsque des lettres ou des chiffres sont peints, notamment lorsqu'il s'agit de chiffres romains, constitués de traits droits.In addition to the problem of the deformation of the substrate, the enamel dials of non-circular shape, pose problems of adhesion and difference in coefficient of expansion between the substrate and the white enamel. In addition, when the white enamel and the paint covering it at least partially are protected by a finishing flux, which is a layer of transparent enamel, cracks can occur in the finishing flux, especially in curved areas of the dial shape, due to the too low hardness of the white enamel which behaves like a moving element. For the same reason the fondant layer does not adhere to white enamel. The painted coating deposited on the white enamel layer also poses a problem of deformation of the painted lines. This distortion problem is particularly apparent when letters or numbers are painted, especially when it comes to Roman numerals, consisting of straight lines.

Ceci montre la complexité des problèmes à résoudre pour pouvoir réaliser un cadran émail de forme non circulaire, en particulier un cadran galbé, qui ne se déforme pas, dont l'émail ne se fissure pas et dont les traits du décor et/ou des inscriptions peintes ne se déforment pratiquement pas, tout au moins de façon perceptible.This shows the complexity of the problems to be solved in order to be able to produce an enamel dial of non-circular shape, in particular a curved dial, which does not deform, whose enamel does not crack and whose features of the decoration and / or inscriptions painted practically do not deform, at least perceptibly.

Le but de la présente invention consiste à résoudre les problèmes susmentionnés en vue de pouvoir remédier aux défauts constatés sur les cadrans émail de forme non circulaire pour montres, plus particulièrement pour montres bracelets.The object of the present invention is to solve the above problems in order to be able to remedy the faults found on non-circular enamel dials for watches, more particularly for wristwatches.

A cet effet, la présente invention a tout d'abord pour objet un cadran émail pour montre selon la revendication 1. Elle a également pour objet un procédé de fabrication d'un cadran émail pour montre, de forme non circulaire selon la revendication 5.To this end, the present invention firstly relates to an enamel dial for watches according to claim 1. It also relates to a method of manufacturing an enamel dial for watches, of non-circular shape according to claim 5.

La description qui suit donnera plusieurs exemples de réalisations de cadrans émail de formes non circulaires pour montres, selon la présente invention.The description which follows will give several examples of embodiments of enamel dials of non-circular shapes for watches, according to the present invention.

Le substrat utilisé dans ces exemples est de l'acier doux à très faible teneur en carbone, inférieure à 0,08% et de préférence à 0,004%. Il s'agit de tôles laminées à froid pour émaillage par vitrification. Les aciers utilisés sont désignés DC03ED ou DC04ED selon la norme européenne EN 10027-1.The substrate used in these examples is mild steel with a very low carbon content, less than 0.08% and preferably 0.004%. These are cold-rolled sheets for vitrification glazing. The steels used are designated DC03ED or DC04ED according to European standard EN 10027-1.

Ces tôles d'acier doivent être traitées avant émaillage pour obtenir, d'une part une surface parfaitement dégraissée, d'autre part une structure superficielle homogène. Il faut en effet éliminer les produits qui recouvrent les tôles laminées, constitués d'un mélange de graisses d'emboutissage et d'huile anticorrosives.These steel sheets must be treated before enameling to obtain, on the one hand a perfectly degreased surface, on the other hand a homogeneous surface structure. It is indeed necessary to eliminate the products which cover the rolled sheets, made up of a mixture of drawing greases and anticorrosive oil.

Le dégraissage peut se faire soit par brûlage, par traitement aux hydrocarbures, ou par dégraissage alcalin, suivi de plusieurs rinçages. Cette opération est suivie d'un décapage à l'acide sulfurique dilué (60 à 90g d'acide concentré de densité 1,84/l d'eau), pendant une dizaine de minutes à température supérieure à 70°C, immédiatement suivie d'une neutralisation dans un bain légèrement alcalin à 0,3-0,5% Na2O à 65-80°C, puis séchage à l'air chaud.Degreasing can be done either by burning, by treatment with hydrocarbons, or by alkaline degreasing, followed by several rinses. This operation is followed by pickling with dilute sulfuric acid (60 to 90g of concentrated acid with a density of 1.84 / l of water), for ten minutes at a temperature above 70 ° C, immediately followed by neutralization in a slightly alkaline bath at 0.3-0.5% Na 2 O at 65-80 ° C, then drying with hot air.

Le substrat ainsi préparé est alors prêt à recevoir une couche d'émail de masse qui constitue d'une part un agent d'adhérence entre le support et la couverte d'émail blanc qui sera déposée ultérieurement, d'autre part permet d'équilibrer les dilatations entre le substrat et la couverte d'émail blanc. Cette couche d'émail de masse permet encore d'absorber les gaz qui se dégagent de la tôle au moment de la cuisson.The substrate thus prepared is then ready to receive a layer of mass enamel which on the one hand constitutes an agent of adhesion between the support and the white enamel covering which will be deposited later, on the other hand makes it possible to balance the expansions between the substrate and the white enamel covering. This mass enamel layer also makes it possible to absorb the gases which emanate from the sheet during cooking.

L'émail de masse utilisé dans les exemples qui vont suivre présente la composition suivante, exprimée en g : Fritte dure 40 20 20 Fritte moyenne 40 40 30 Fritte tendre 20 40 50 Quartz 10 Argile 6 Bentonite 0,25 Nitrite de sodium 0,10 Borax 0,50 Carbonate de magnésium 0,15 Eau 50 à 55 The mass enamel used in the following examples has the following composition, expressed in g: Hard frit 40 20 20 Medium frit 40 40 30 Soft frit 20 40 50 Quartz 10 Clay 6 bentonite 0.25 Sodium nitrite 0.10 Borax 0.50 Magnesium carbonate 0.15 Water 50 to 55

La barbotine d'émail préparée à l'aide de cette composition est broyée jusqu'à l'obtention de la finesse et de la densité désirée, déterminées expérimentalement, étant entendu qu'une trop grande finesse augmente la tension superficielle de l'émail et peut provoquer un retrait. Ensuite elle est passée dans un séparateur magnétique pour enlever les particules ferreuses.The enamel slip prepared using this composition is ground until the desired fineness and density are obtained, determined experimentally, it being understood that too great a fineness increases the surface tension of the enamel and may cause withdrawal. Then it is passed through a magnetic separator to remove the ferrous particles.

La couche d'émail de masse est déposée sur tout le substrat (recto, verso et tranche) à l'aide d'un pistolet de projection, suivi d'un séchage destiné à éliminer l'eau avant la cuisson de l'émail de masse. Tous les modes de séchage habituels peuvent être utilisés, à l'air libre, dans une étuve ou par rayonnement.The mass enamel layer is deposited on the entire substrate (front, back and edge) using a spray gun, followed by drying intended to remove the water before the enamel is cooked. mass. All the usual drying methods can be used, in the open air, in an oven or by radiation.

Ensuite l'émail de masse est cuit dans un four box électrique chauffé entre 760° et 860°C de façon à obtenir un revêtement uniforme.Then the mass enamel is fired in an electric box oven heated between 760 ° and 860 ° C so as to obtain a uniform coating.

La préparation de l'émail blanc est réalisé à partir de produits du commerce disponibles à l'état pulvérulent ou en morceaux. Dans un cas comme dans l'autre, ce produit doit être broyé pour obtenir une poudre fine aux grains réguliers dont la grosseur se situe aux environs de 10 à 15 µm. Pour réduire le plus possible la contamination de la poudre d'émail par des corps étrangers, le broyage s'effectue de préférence dans un broyeur en agathe. De l'eau distillée est ajoutée à la poudre et le broyage est entrecoupé de plusieurs lavages pour éliminer les impuretés et le limon constitué par les plus fines particules d'émail qui restent en suspension dans l'eau.The preparation of white enamel is made from commercial products available in powder form or in pieces. In either case, this product must be ground to obtain a fine powder with regular grains, the size of which is around 10 to 15 µm. To minimize contamination of the enamel powder by foreign bodies, the grinding is preferably carried out in an agate grinder. Distilled water is added to the powder and the grinding is interspersed with several washes to remove the impurities and the silt formed by the finest particles of enamel which remain in suspension in the water.

Le broyage à partir de morceaux est évidemment plus long qu'à partir de poudre plus ou moins grossière. Par contre, celle-ci contient beaucoup plus d'impuretés provenant des tamis, des filtres magnétiques et des revêtements des broyeurs.Grinding from pieces is obviously longer than from more or less coarse powder. On the other hand, this one contains much more impurities coming from the sieves, magnetic filters and coatings of the crushers.

L'émail obtenu est alors acidifié à l'aide d'acide nitrique dilué à 40% (60% d'acide dans 40% d'eau) pour dissoudre les éléments métalliques non assimilés au sein de l'émail, les sels divers issus de l'émail durant son broyage (limon) et pour dissoudre les matières organiques qui peuvent se trouver en suspension dans l'eau.The enamel obtained is then acidified using nitric acid diluted to 40% (60% acid in 40% water) to dissolve the non-assimilated metallic elements within the enamel, the various salts derived enamel during grinding (silt) and to dissolve organic matter which may be in suspension in water.

Un autre effet de l'acidification de l'émail est de le durcir. Ce durcissement étant directement lié à la proportion d'acide introduit dans la barbotine d'émail, ce qui permet de régler la dureté de la couche d'émail, comme on l'expliquera par la suite.Another effect of the acidification of the enamel is to harden it. This hardening is directly linked to the proportion of acid introduced into the enamel slip, which makes it possible to adjust the hardness of the enamel layer, as will be explained below.

L'ajustement de cette dureté constitue une opération de grande importance pour le succès final. En effet, comme expliqué précédemment, la bonne dureté de l'émail blanc est la condition pour que la couche de fondant de finition ne se fissure pas, notamment au niveau du galbe. Les essais réalisés on montré que la dureté de l'émail blanc doit se situer entre 5 et 6, de préférence autour de 5,5, sur l'échelle de Mohs, utilisée pour mesurer la dureté des matières minérales. En outre, la bonne dureté de l'émail blanc est la condition pour que les traits peints à sa surface ne se déforment pas.Adjusting this hardness is an operation of great importance for final success. Indeed, as explained previously, the good hardness of the white enamel is the condition so that the finishing fondant layer does not crack, in particular at the level of the curve. The tests carried out have shown that the hardness of the white enamel must be between 5 and 6, preferably around 5.5, on the Mohs scale, used to measure the hardness of mineral materials. In addition, the good hardness of the white enamel is the condition so that the lines painted on its surface do not deform.

La pratique a montré que la mesure de dureté sur l'échelle de Mohs est une mesure grossière, manquant de sensibilité dans le cas de la présente invention. En pratique, pour les besoins de l'invention, cette dureté est ajustée en se basant sur la déformation des traits de peinture à sa surface, ainsi que sur l'absence de fissure de la couche de fondant de finition, c'est-à-dire en fonction du résultat obtenu. L'ajustement de cette dureté varie d'un émail à l'autre et ne peut être déterminée que de façon empirique. Pour un même émail, cet ajustement est par contre parfaitement reproductible.Practice has shown that the hardness measurement on the Mohs scale is a rough measurement, lacking in sensitivity in the case of the present invention. In practice, for the purposes of the invention, this hardness is adjusted based on the deformation of the paint lines on its surface, as well as on the absence of cracking of the finishing fondant layer, that is to say - say according to the result obtained. The adjustment of this hardness varies from one enamel to another and can only be determined empirically. However, for the same enamel, this adjustment is perfectly reproducible.

Une fois que l'émail à été broyé à la granulométrie désirée et acidifié, il est stocké dans des boîtes hermétiques. Une partie de l'émail est mouillé avec de l'eau distillée, l'autre partie est séchée. L'émail mouillé est appliqué au pinceau puis séché avant d'être cuit entre 700° et 790° dans un four box. Il est ensuite refroidi lentement puis dégraissé à l'alcool industriel.Once the enamel has been ground to the desired particle size and acidified, it is stored in airtight containers. Part of the enamel is wetted with distilled water, the other part is dried. The wet enamel is applied with a brush and then dried before being baked between 700 ° and 790 ° in an oven box. It is then slowly cooled and then degreased with industrial alcohol.

On applique ensuite une deuxième couche d'émail séché, à l'aide d'un tamis très fin et on procède à une deuxième cuisson. Enfin on applique une nouvelle couche d'émail séché suivie d'une cuisson. Lorsque l'émail est froid, il est dégraissé et repassé au four pour égaliser les trois couches.A second layer of dried enamel is then applied, using a very fine sieve, and a second firing is carried out. Finally, apply a new layer of dried enamel followed by firing. When the enamel is cold, it is degreased and ironed in the oven to even out the three layers.

On procède alors au lapidage de l'émail avec un papier abrasif de 15µ - 9µ et de l'eau pour éviter l'échauffement, jusqu'à l'obtention d'une épaisseur désirée régulière sur toute la surface du cadran.The enamel is then stoned with 15µ - 9µ sandpaper and water to avoid overheating, until a regular desired thickness is obtained over the entire surface of the dial.

L'égalisation finale s'effectue après un nouveau dégraissage à l'alcool, en repassant le cadran au four entre 700° et 790°C. L'émail dépoli durant le lapidage se vitrifie et se retend. Cette opération peut être répétée si nécessaire.The final equalization is carried out after a further degreasing with alcohol, by ironing the dial in the oven between 700 ° and 790 ° C. The frosted enamel during stoning becomes vitrified and tightened. This can be repeated if necessary.

A ce stade, l'épaisseur du cadran est au maximum de 1,1 mm, comprenant l'épaisseur du substrat, celle de l'émail de masse recouvrant les deux faces du substrat et celle de l'émail blanc.At this stage, the thickness of the dial is at most 1.1 mm, including the thickness of the substrate, that of the mass enamel covering the two faces of the substrate and that of the white enamel.

La prochaine étape consiste à déposer la peinture. Cette peinture comprend les chiffres et les caractères destinés à indiquer les heures, les minutes et divers indications relatives notamment à la marque. Cette peinture peut aussi être décorative et comporter plusieurs couleurs, en utilisant les peintures vitrifiables habituelles vendues pour l'émail et qui sont généralement constituées par des pigments d'oxydes métalliques que l'on mélange à une essence grasse ou un autre milieu de dispersion approprié, dans une proportion fonction de la consistance souhaitée.The next step is to deposit the paint. This painting includes the numbers and the characters intended to indicate the hours, the minutes and various indications relating in particular to the mark. This paint can also be decorative and include several colors, using the usual vitrifiable paints sold for enamel and which generally consist of metallic oxide pigments which are mixed with a fatty essence or another suitable dispersion medium. , in a proportion depending on the desired consistency.

Ces couleurs vitrifiables sont broyées très finement et sont appliquées au pinceau sur l'émail blanc puis elles sont cuites entre 750°C et 830°C, ce qui a pour effet de vitrifier les couleurs et de les incruster dans l'émail blanc.These vitrifiable colors are ground very finely and are applied with a brush to the white enamel, then they are fired between 750 ° C and 830 ° C, which has the effect of vitrifying the colors and embedding them in the white enamel.

La dernière opération consiste à appliquer le fondant de finition. La préparation de ce fondant s'effectue par broyages et lavages alternés comme pour l'émail blanc sans adjonction d'acide nitrique, pendant environ 35 minutes. Cette opération a pour but d'améliorer la transparence du fondant de finition. Lorsqu'il est suffisamment broyé et lavé, le fondant de finition est séché.The last step is to apply the finishing fondant. This fondant is prepared by alternating grinding and washing as for white enamel without the addition of nitric acid, for approximately 35 minutes. The purpose of this operation is to improve the transparency of the fondant finish. When sufficiently ground and washed, the finishing fondant is dried.

Il est appliqué au tamis par couches successives avec une cuisson entre chaque couche. Au total une dizaine de couches sont appliquées, chaque couche étant cuite entre 650° et 750°C. L'épaisseur totale de la couche de fondant de finition est de l'ordre de 0,1 mm.It is applied to the sieve in successive layers with cooking between each layer. A total of ten layers are applied, each layer being cooked between 650 ° and 750 ° C. The total thickness of the finishing fondant layer is of the order of 0.1 mm.

Deux sortes d'émail blanc ont été utilisées pour effectuer les essais. Le premier provient de la cristallerie de Saint-Paul, Limoges, France et porte la référence « Blanc 160 », tandis que le second est fabriqué par Blythe, Londres, Grande-Bretagne.Two kinds of white enamel were used to carry out the tests. The first comes from the Saint-Paul crystal factory, Limoges, France and bears the reference "Blanc 160", while the second is manufactured by Blythe, London, Great Britain.

10 g d'émail « Blanc 160 » ont été broyés quatre fois 4 min avec lavages alternés. Il a ensuite été traité à l'acide nitrique (10 gouttes) pendant dix minutes, ce qui permet d'assurer une bonne tenue de la peinture et d'éviter au fondant de finition de se fissurer.10 g of "White 160" enamel were ground four times 4 min with alternating washes. It was then treated with nitric acid (10 drops) for ten minutes, which ensures good hold of the paint and prevents the finishing flux from cracking.

10 g d'émail blanc 263T6 de Blythe vendu par Johnson Mattey ont été broyés 6x4 min. Ensuite la poudre est traitée à l'acide avec deux gouttes de l'acide nitrique susmentionné pendant 5 min.10 g of 263T6 white enamel from Blythe sold by Johnson Mattey were ground 6x4 min. Then the powder is treated with acid with two drops of the aforementioned nitric acid for 5 min.

La peinture s'adapte parfaitement à la texture du fond blanc et le fondant de finition ne se fissure pas lors du lapidage.The paint adapts perfectly to the texture of the white background and the finishing flux does not crack during stoning.

Il ressort des essais effectués, que pour chaque type d'émail on doit effectuer des essais pour fixer les paramètre du procédé, en particulier pour adapter la dureté de la couche d'émail blanc pour éviter la déformation de la peinture et les fissures dans le fondant de finition.It appears from the tests carried out, that for each type of enamel, tests must be carried out to fix the parameters of the process, in particular to adapt the hardness of the white enamel layer to avoid deformation of the paint and cracks in the fondant finish.

Claims (9)

Cadran émail pour montre, caractérisé en ce qu'il présente un substrat en acier doux de forme autre que circulaire dont l'épaisseur est d'au moins 0,45 mm, dont au moins le recto et le verso sont recouverts d'un agent d'adhérence et en ce que sur la partie couvrant le recto dudit substrat s'étend une épaisseur d'émail blanc dont une partie au moins est recouverte d'un décor et/ou d'inscriptions peintes.Enamel dial for watches, characterized in that it has a mild steel substrate of a shape other than circular, the thickness of which is at least 0.45 mm, of which at least the front and back are covered with an agent adhesion and in that on the part covering the front of said substrate extends a thickness of white enamel, at least part of which is covered with a decoration and / or painted inscriptions. Cadran émail selon la revendication 1, dans lequel ledit agent d'adhérence est un émail de masse qui recouvre au moins ses deux faces.Enamel dial according to claim 1, in which said adhesion agent is a mass enamel which covers at least its two faces. Cadran émail selon l'une des revendications précédentes dans lequel ledit substrat métallique est en acier décarburé dont la teneur en carbone n'est pas supérieure à 0,08%, de préférence pas supérieure à 0,004%.Enamel dial according to one of the preceding claims, in which said metallic substrate is made of decarburized steel the carbon content of which is not more than 0.08%, preferably not more than 0.004%. Cadran émail selon l'une des revendications précédentes, dans lequel ledit substrat est galbé.Enamel dial according to one of the preceding claims, in which said substrate is curved. Cadran émail selon l'une des revendications précédentes, dans lequel une épaisseur de fondant de finition recouvre ledit émail blanc et le décor et/ou les inscriptions peintes qui le recouvre au moins partiellement.Enamel dial according to one of the preceding claims, in which a thickness of finishing fondant covers said white enamel and the decoration and / or painted inscriptions which covers it at least partially. Procédé de fabrication d'un cadran émail pour montre de forme non circulaire, caractérisé en ce que l'on prend un substrat en acier doux présentant la forme désirée, on recouvre ledit substrat d'un agent d'adhésion, on dépose sur elle au moins une couche d'émail blanc dont la dureté est choisie pour permettre de recevoir ultérieurement des traits de peinture sans que ceux-ci ne subissent de déformation substantielle et pour permettre de recevoir un fondant de finition sans qu'il ne se fissure, on cuit cet émail, on lapide et égalise ladite couche, on dépose et on cuit de ladite peinture sur au moins une partie de la surface dudit substrat en fonction du décor et/ou des inscriptions désirées.Method for manufacturing an enamel dial for a watch of non-circular shape, characterized in that one takes a mild steel substrate having the desired shape, one covers said substrate with an adhesion agent, and deposits it on the minus a layer of white enamel, the hardness of which is chosen to allow subsequent paint strokes to be received without them being subjected to substantial deformation and to allow receiving a finishing flux without cracking, baking this enamel, we stone and equalize said layer, we deposit and bake said paint on at least part of the surface of said substrate depending on the decor and / or the desired inscriptions. Procédé selon la revendication 6, selon lequel on enrobe ce substrat avec une épaisseur d'émail de masse en tant qu'agent d'adhérence, on cuit cet émail de masse, on effectue le lapidage de l'épaisseur d'émail de masse recouvrant le recto dudit substrat et on égalise ladite épaisseur d'émail de masse.Method according to claim 6, in which this substrate is coated with a thickness of mass enamel as a bonding agent, this mass enamel is baked, the stoning of the thickness of covering mass enamel is stoned the front of said substrate and equalizing said thickness of mass enamel. Procédé de fabrication selon l'une des revendications précédentes, dans lequel on ajuste la dureté dudit émail blanc en le soumettant à un processus d'acidification.Manufacturing method according to one of the preceding claims, in which the hardness of said white enamel is adjusted by subjecting it to an acidification process. Procédé selon l'une des revendications 6 à 8, selon lequel on dépose une pluralité de couches de fondant de finition pour recouvrir la surface de ladite couche d'émail blanc et de peinture déposée sur elle.Method according to one of claims 6 to 8, according to which a plurality of layers of finishing flux are deposited to cover the surface of said layer of white enamel and of paint deposited on it.
EP02405902A 2002-10-22 2002-10-22 Enamelled watch dial and process for making it Withdrawn EP1413649A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
EP02405902A EP1413649A1 (en) 2002-10-22 2002-10-22 Enamelled watch dial and process for making it
AU2003269661A AU2003269661A1 (en) 2002-10-22 2003-10-17 Enamel dial for watch and method for making an enamel dial
AT03750226T ATE405691T1 (en) 2002-10-22 2003-10-17 ENAMELED WATCH DIAL AND METHOD OF PRODUCTION
EP03750226A EP1554415B1 (en) 2002-10-22 2003-10-17 Enamel dial for watch and method for making an enamel dial
DE60323117T DE60323117D1 (en) 2002-10-22 2003-10-17 ENAMELED CLOCK LEAF AND METHOD OF MANUFACTURE
PCT/CH2003/000678 WO2004038066A2 (en) 2002-10-22 2003-10-17 Enamel dial for watch and method for making an enamel dial
HK05106355.1A HK1074062A1 (en) 2002-10-22 2005-07-26 Enamel dial for watch and method for making an enamel dial

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EP02405902A EP1413649A1 (en) 2002-10-22 2002-10-22 Enamelled watch dial and process for making it

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EP03750226A Expired - Lifetime EP1554415B1 (en) 2002-10-22 2003-10-17 Enamel dial for watch and method for making an enamel dial

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AT (1) ATE405691T1 (en)
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH716545A1 (en) * 2019-08-28 2021-03-15 Patek Philippe Sa Geneve Process for decorating a watch element.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR820983A (en) * 1936-07-27 1937-11-24 Process for enamelling sheets, particularly applicable to decorative coatings
DE3323758C1 (en) * 1983-07-01 1984-07-19 Bernd 4000 Düsseldorf Deckert Clock face

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3223028A1 (en) * 1981-06-24 1983-01-05 Ise Kogyo K.K., Osaka Product having cloisonné enamelling

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR820983A (en) * 1936-07-27 1937-11-24 Process for enamelling sheets, particularly applicable to decorative coatings
DE3323758C1 (en) * 1983-07-01 1984-07-19 Bernd 4000 Düsseldorf Deckert Clock face

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH716545A1 (en) * 2019-08-28 2021-03-15 Patek Philippe Sa Geneve Process for decorating a watch element.

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WO2004038066A3 (en) 2004-10-28
ATE405691T1 (en) 2008-09-15
WO2004038066A2 (en) 2004-05-06
EP1554415A2 (en) 2005-07-20
DE60323117D1 (en) 2008-10-02
EP1554415B1 (en) 2008-08-20
AU2003269661A1 (en) 2004-05-13
HK1074062A1 (en) 2005-10-28

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