Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/02—Surface treatment of glass, not in the form of fibres or filaments, by coating with glass
  • C03C17/04—Surface treatment of glass, not in the form of fibres or filaments, by coating with glass by fritting glass powder
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
  • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
  • B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
  • B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
  • B32B17/10165—Functional features of the laminated safety glass or glazing
  • B32B17/10339—Specific parts of the laminated safety glass or glazing being colored or tinted
  • B32B17/10348—Specific parts of the laminated safety glass or glazing being colored or tinted comprising an obscuration band
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
  • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
  • B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
  • B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
  • B32B17/10807—Making laminated safety glass or glazing; Apparatus therefor
  • B32B17/10889—Making laminated safety glass or glazing; Apparatus therefor shaping the sheets, e.g. by using a mould
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
  • C03B23/025—Re-forming glass sheets by bending by gravity
  • C03B23/0252—Re-forming glass sheets by bending by gravity by gravity only, e.g. sagging
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/02—Frit compositions, i.e. in a powdered or comminuted form
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
  • C03C8/16—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions with vehicle or suspending agents, e.g. slip
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C2205/00—Compositions applicable for the manufacture of vitreous enamels or glazes
  • C03C2205/02—Compositions applicable for the manufacture of vitreous enamels or glazes for opaque enamels or glazes

Definitions

• the present invention relates to automotive glazings comprising enamelled patterns.
• the glazings comprising an enamelled part offer particularities both as regards certain heat treatments, bending or quenching, or as regards the properties of the glazing in question.
• the accent is put in the following on the aspect relating to the heat treatments but also on the properties which derive from the characteristics of these glazings.
• enamelled strips modifies the local behavior of the glass sheets vis-à-vis the heat transfer during their shaping.
• these enamels arranged on essentially transparent glass sheets are, for their part, mainly opaque to visible radiation but especially to infrared radiation.
• Thermal transfers in the bending or quenching furnaces are for the most part related to the radiative mode, even if a significant part can be of the convective type.
• the radiative mode of heat transfer is for the most part concentrated in the near infrared
• FIRE REPLACEMENT LIGHT (RULE 26) (789-2500nm) or far (more than 2500nm) and for less in the visible.
• Clear glass absorbs infrared radiation, but this absorption is significant, especially when its temperature rises, remains lower than that observed for opaque enamel products, especially when the color of these is very dark, which is the case of the most used products for the masking which has been mentioned above.
• the bending of the leaves can be carried out according to different techniques. In all cases, however, the presence of enamelled parts intervenes on the thermal conditioning of the leaves.
• these techniques the most sensitive to the establishment of precise temperature conditions are those which comprise at least partially a "gravity" forming step. In these techniques the shaping of the glass takes place, when the latter is at its softening temperature, under the effect of its own weight. In this case, the glass sheets being supported only at their periphery, the forces acting locally are greater at the edge than at the center of the sheets, leading to greater deformation, making it difficult to obtain the shape. desired. This type of difficulty is encountered as soon as a part of the process comprises deformation by gravity, even if the technique also includes accessory methods such as localized partial pressing.
• Successful shaping involves controlling the local temperature conditions at the different points on the surface of the leaves, a higher temperature favoring more intense deformation and vice versa.
• the edges should be kept at a lower temperature than the center of the sheets. To achieve this result it is traditional to control the absorption of glass by transferring part of the thermal input locally to the elements that accompany the glazing during bending, and / or by modifying the distribution of radiation on the curved sheet or leaves by adding infrared sources.
• thermal masses made of metal plates are distributed around the perimeter of the sheet support. These thermal masses absorb a controlled portion of the infrared radiation opposite the areas of the enamel-coated sheets likely to absorb more heat than the neighboring uncoated areas. This mode of control is not perfectly satisfactory even if it makes it possible to obtain bumps having the essential geometrical characteristics desired. In practice the adjustment of thermal masses to the need for absorption requires multiple tests and a great experience in this field. But the presence of these thermal masses has other disadvantages.
• the invention proposes to respond at least in part to the difficulties stated with regard to the production of glazing comprising enamelled parts and if necessary to improve the properties of these windows.
• the invention provides glazings such as those which are the subject of claim 1.
• glazing according to the invention it is appropriate to choose enamelled compositions which while giving a high opacity to the coated parts, limit the absorption infrared radiation from these coatings.
• the reflected part must not exceed that which would lead to insufficient heating of the glasses located under these enamels with respect to the incident IR rays.
• the limit in question is a function of various parameters which are related to the configuration of the furnace, the arrangement of the sources of radiation, the material on which the glass sheets are arranged, and the glass sheets themselves.
• the reflection of the enamelled parts measured according to the ISO 9050 standard preferably does not exceed 30% of the lengths of glass. wave of more than 800nm, and more commonly, no more than 25% of these wavelengths.
• Glazing according to the invention must simultaneously have a light transmission that corresponds to the type of glazing considered, windshield, rear window, roof, side windows ..., but also whose parts having an enamelled coating are essentially opaque to the visible.
• the masking function for these enamelled parts leads to a light transmittance of the visible range that is practically zero. This transmission must be less than 1% and generally less than 0.1% measured according to EN 410. This concerns only the coated parts. Glazing often has edge edges enamelled edges made of points providing progressive masking. These selvedges present a transmission that decreases from the uncoated part of the glazing to that in which the enamelled layer is uniform.
• Glazing for the automotive sector shall comply with the characteristics prescribed by regulations or practice for these uses.
• the reflection in the wavelengths of the visible glazing should not be too important to maintain a good light transmission of the transparent parts, but also not to generate a mirror effect.
• the enamelled parts must not present a reflection too important of the visible field.
• reflection in the visible range should not be too important to maintain a good light transmission of the transparent parts, but also not to generate a mirror effect.
• the enamelled parts must not present a reflection too important of the visible field.
• (Remail) measured according to EN 410 preferably should not exceed 25%, particularly preferably not more than 20%, and preferably not more than 10%.
• the reflection of the glazing in the visible does not show a strong difference between the coated parts and those which are not (Rverre). This difference is advantageously less than 10% and preferably less than 5%.
• the implementation of the invention in bending techniques allows better local control of the temperature of the shaped sheets and especially in the steps of modifying the sheets under the effect of their own weight.
• the invention is advantageously applicable that the bending is performed entirely by gravity or that the process comprises elements of forming by pressing of the sheets, in particular pressings concerning only certain parts of the glazing, as is often the case for glazings with locally very pronounced curvatures.
• the implementation of the invention is particularly useful when the bending is performed simultaneously on two sheets for subsequent assembly by means of a polyvinyl butyraal (PVB) thermoplastic interlayer sheet.
• PVB polyvinyl butyraal
• the glass sheets that are part of the composition of laminated glazings have the enamelled parts either on the face 2 or on the face 4, according to the traditional name which leads to the numbering of the faces of the glass sheets from that facing outwards. of the vehicle.
• the enamelled parts can be either between the two sheets of glass, or on the face of the upper sheet directly exposed to infrared. The choice between these two positions is at least partly a function of the enamel and its treatment.
• the applied layer may undergo no treatment prior to introduction into the bending and / or quenching furnace.
• the coating goes through the different stages of cooking as the temperature rises.
• the first step leads to the removal of the most volatile solvents and possibly organic constituents used in the composition of the enamel pastes.
• the coating is no longer "tacky".
• the temperature of the glass sheets continuing to rise, the fried contained in the enamel paste is brought to its melting point and the glass sheets reach their state of softening which leads to bending.
• the enamel composition is only in contact with the atmosphere. It is not likely to be moved or altered.
• the simultaneous bending of two sheets also leads in some cases to the reversal of the order of the sheets in the final assembled glazing.
• the bending being performed the sheet in the upper position during the bending is placed below for assembly. This way allows to proceed with the enamelled coating exposed to the atmosphere on the upper sheet during bending. In other words cooking can be conducted as in the first case indicated above, with or without pre-cooking enamel while having the enamel in position 2 in the laminated glazing.
• the invention is applicable to all glazing irrespective of the thickness of the sheets or their possible color. It has particularly sensitive advantages for the bending of the least thick leaves. Controlling the thermal conditions for these sheets is difficult to ensure because of their lower thermal inertia. It is therefore very useful to improve this control by implementing the provisions of the invention.
• infrared-reflecting enamels also offers advantages for the glazings obtained.
• the fact of having enamels whose characteristic compared to traditional masking enamels is to reflect a significantly greater share of infrared radiation can reduce heating of elements of the glazing or those which are in contact with this glazing when these windows are exposed to solar radiation.
• a lower heating of the enamelled edges of a glazing avoids too fast aging adhesives gluing the glazing to the vehicle body. This is particularly noticeable on glazing that is highly exposed to solar radiation, such as roofs.
• the implementation products according to the invention makes it possible to improve the protection of the heat-sensitive functional elements that may comprise these glazings in the immediate vicinity, possibly partially under these enamelled parts. This is for example the case of materials used in the composition of certain glazing whose light transmission is electro-controlled, including those which include particles such as cells called "SPD" (suspended particle device).
• FIG. 2a represents the state of the thermal masses necessary for a frame bending of a windshield model with a usual enamel
• FIG. 1 compares the reflection spectra as a function of the wavelengths of enamels conventionally used on automotive glazing on the one hand and enamels meeting the criteria of the invention on the other hand. All enamels used are based on mineral pigments. Applied pastes contain solvents, binders and fries in addition to dark colored pigments based on metal oxides, especially iron oxide.
• the application of the paste leads to an enamel layer of 40 ⁇ thick.
• the reflection measurements are carried out by exposing the enamel layer directly to the radiation, the glass only serving as a support.
• the traditional enamel composition has a reflection A that is practically uniform over the entire infrared spectrum.
• the level of reflection is of the order of 5%.
• the spectrum of enamel corresponding to the invention B has a very rapidly increasing reflection for wavelengths greater than 750 nm. This reflection increases to a level that is about 35%.
• the two samples are placed in the open air side by side and flat against a source of infrared radiation of limited power. Both samples are identically exposed. The temperature rise of the glass sheets is measured. Under the conditions of the test, the temperature stabilizes after 10 minutes of exposure.
• the temperature of the sample coated with traditional enamel is 92 ° C, that of the enamel whose reflection of the infrared is increased to 77 ° C. For exposure to low power infrared radiation, a significant difference is thus obtained.
• This mechanism is applied in a series of tests relating to the bending of glass sheets of a windshield model. The bending is conducted entirely by gravity on the two superimposed sheets. The cut leaves are placed horizontally on frames intended to support their periphery in the bending. The entire frame and two sheets is passed through a so-called "tunnel" furnace in which the temperature rises gradually to reach the temperature of deflection of the glass with a good distribution of the temperature on the surface of the leaves. The progression in the oven must be fast enough for reasons of economic efficiency. The residence time in the oven to the deflection of the leaves that are applied against the frame that supports them, in this case is 12 minutes.
• the temperature In the distribution of temperatures on the surface of the leaves it is important to ensure that the parts which are subjected to the most important forces of gravity do not undergo an excessive deformation with respect to that of the central parts of the leaves. To avoid undesirable deformation, the temperature must be lower on the edges of the glass sheets.
• the temperature control for the windshield model leads to maintaining a ten or so degrees of difference between the center of the sheets and the edges thereof, respectively about 625.degree. and 615 ° C.
• the two sheets are ordinary "float" glass and each have a thickness of 2.1mm.
• the enamel is applied on the edges of the upper sheet on the face directly exposed to the radiation.
• the bending being completed, the order of the sheets is reversed during the subsequent assembly.
• the width of the enamelled strip varies according to the location thereof. It is about 2.5cm on the side edges, 5cm at the top of the windshield with an extension at the location of the mirror brackets and rain or light sensors, up to 15cm, and about 16cm in the bottom of the windshield.
• the support frames used are provided with thermal masses consisting of steel plates. These plates arranged under the glass sheets are in planes substantially parallel to these sheets. The presence of these plates is necessary in front of the parts having the widest enamelled strips at the top and bottom of the windshield, with a particularly sensitive point corresponding to the location of attachment of the mirror and the various sensors.
• Figures 2a and 2b are the representation of the location and shape of the heat masses relative to the glass sheets. On each plate its thickness in millimeters is indicated. The choice of masses is such that the result obtained is practically identical, or even improved, in the case of the invention as regards the shape obtained but also the optical and mechanical characteristics of these glazings.
• Figure 2a presents the case of the use of traditional low reflection enamel.
• the thickness of the plates used as thermal masses appears all the more important that they are under the largest enamelled areas. Also in this example the most sensitive point is the one at the center of the upper part where two superimposed plates are needed totaling 11.5mm thick.
• the set of thermal masses for identical conditions of passage in the oven has reduced thicknesses. The evolution is particularly noticeable in the fixing area of the mirror. In this area the plate goes from 11.5mm to 5mm thick. But all plates have a reduced thickness of at least 2mm.
• thermal masses allow a more convenient maintenance of the tooling, but especially results in a reduction of the energy consumption.
• Part of the energy consumed is used to heat these thermal masses.
• the energy thus expended does not contribute to the heating operation of the glass. It is lost to the extent that the frames after bending the sheets, and out of the oven, are cooled to room temperature in the circuit which leads them to a new cycle of use.
• the energy consumption related to the temperature rise of the thermal masses is of the order of 10% of that used for heating the glass itself, and about 1.5% of the total energy. consumed in the oven.
• the reduction of the order of 30% of these masses therefore allows a reduction of the order of 0.5% of the total energy consumption.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Joining Of Glass To Other Materials (AREA)
• Glass Compositions (AREA)

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• 2011
  • 2011-08-12 BE BE2011/0493A patent/BE1020191A3/fr not_active IP Right Cessation
• 2012
  • 2012-07-03 US US14/238,676 patent/US20160185656A1/en not_active Abandoned
  • 2012-07-03 EP EP12730988.8A patent/EP2742011A1/de not_active Withdrawn
  • 2012-07-03 WO PCT/EP2012/062889 patent/WO2013023832A1/fr not_active Ceased

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