Glass unit, especially coated glass unit

0001The invention relates to a glass unit, in particular an optically coated glass unit, with an opaque area and with a translucent area, which has a composite surface in the opaque area for fastening the glass unit with the aid of an adhesive. - Glass unit referred to in the context of the invention simple glass panes, also toughened safety glass panes or laminated glass panes, such as those used for. B. are common as motor vehicle windows, facade panels and the like, but also insulating glass units from the outer pane, inner pane, space between panes and spacers at the edge between the outer pane and the inner pane. The insulating glass units can have an air filling or a gas filling and, if appropriate, further glass panes. In particular, the invention relates to glass units for so-called structural glazing. If it is an optically tempered glass unit, this can have an opto-coating. Opto-coating refers to any coating on the glass unit that has an effect that can be perceived by eye inspection in the visible range of the light spectrum, regardless of whether the opto-coating is primarily used for another purpose, e.g. B. as a UV protective layer or as an IR reflection layer, is aimed. Mainly in the context of the invention, the opto-coating is an optically effective coating. The opto-coating is translucent. The glass panes of the glass unit can consist of clear glass or of colored glass.

0002Glass units as described above are generally attached to a support with the aid of an adhesive, e.g. B. connected to the molded in the body of a motor vehicle metallic window frame. However, the carrier can also be the spacer frame of an insulating glass unit or a carrier for facade cladding. As an adhesive z. B. silicones, polysulfides, polyurethanes and others used. They are usually more or less sensitive to light and age over time when exposed to light. Exposure to light here means in particular the incidence of electromagnetic radiation in the visible spectral range, in particular UV radiation.

0003In order to prevent the adhesive from aging and being damaged by exposure to light in the described glass units, it is known to provide special adhesive protective layers. They are arranged in the area of ​​the composite surface in such a way that they shield the adhesive against light coming from outside. The adhesive protective layers are mostly black enamel layers and are typically applied and baked onto the surface of the associated glass pane using a screen printing process. The printing pastes used are enamel colors and form an enamel bond with the assigned surface of the glass unit when baked. In this respect, they have a ceramic character and their connection to the glass surface is ceramic. This applies to all printing inks that are dealt with below in the context of the invention.

0004If the composite surface of a glass unit of the construction described is provided with a black adhesive protective layer, this black border is disruptive in many applications for aesthetic reasons. The reason for this is that the reflection characteristics (the external views) of the translucent area and the opaque area comprising the adhesive protective layer differ significantly from one another in such glass units, that is to say the composite surface is clearly perceptible when viewed from the outside. This applies in particular if there is at least one optical coating which modifies the reflection behavior of the glass unit in the translucent area. If the opto-coating were also arranged in the area of ​​the composite surface and the adhesive protective layer was applied thereon, the adhesive-protective layer would normally destroy the opto-coating during baking.

0005The invention is based on the technical problem of largely reducing the differences in the reflection behavior of the opaque and the translucent area in a glass unit of the construction described and the intended use described, without making compromises in protecting the adhesive from aging by exposure to light.

0006To solve this technical problem, the subject of the invention is a glass unit, in particular an optically coated glass unit, with an opaque area and with a translucent area, possibly with an opto-coating, which has a composite surface in the opaque area for fastening the glass unit with the aid of an adhesive, with the following characteristics:<dl id="dl0001"><dt>1.1)</dt><dd>In the opaque area - seen from the outside, a printed and baked-on masking layer is initially arranged, which has dye admixtures, and behind it an opaque adhesive protective layer,</dd><dt>1.2)</dt><dd>the masking layer is designed in such a way that the reflection characteristic in the visible spectral range of the opaque range corresponds at least approximately to that of the translucent range of the glass unit,</dd></dl> the adhesive protective layer protects the adhesive against aging due to exposure to light.

0007According to the invention, the opaque area of ​​the glass unit thus has at least two different layers, one of which - the masking layer - takes on the technical function of largely adapting the reflection characteristics of the opaque area to that of the translucent area, while the other - the opaque area, normally black adhesive protective layer - takes on the technical function of protecting the adhesive to be arranged on the composite surface from harmful light exposure. The decoupling of both functions according to the invention leads in a surprisingly simple manner to an aesthetically satisfactory solution to the problem on which the invention is based.

0008In practice, it has been shown that the reflection characteristics can be approximated if the internationally used parameters L ∗, a ∗, b ∗ (see DIN 6174) for the opaque area and the translucent area differ at most as follows :<maths id="math0001" num=""><math display="block"><mrow><mtext>| L * (opaque area) - L * (translucent area) | &lt;10, vzw. ≤ 5;</mtext></mrow></math><img file="EP0807611A1_D0001.tif" /></maths><maths id="math0002" num=""><math display="block"><mrow><mtext>| a * (opaque area) - a * (translucent area) | ≤ 3, vzw. ≤ 2;</mtext></mrow></math><img file="EP0807611A1_D0002.tif" /></maths><maths id="math0003" num=""><math display="block"><mrow><mtext>| b * (opaque area) - b * (translucent area) | ≤ 3, vzw. &lt;2.</mtext></mrow></math><img file="EP0807611A1_D0003.tif" /></maths>

0009When selecting suitable printing inks for the masking layer, a wide range of commercially available stoving inks suitable for glass printing can be used. If no standard color with suitable reflection characteristics is available, the desired color can be set by mixing two or more colors that are compatible with one another. If the masking layer and the adhesive protective layer are printed directly on top of one another, the color selection for the two layers must also ensure their compatibility with one another (chemical compatibility, similar thermal expansion coefficients, etc.).

0010As already mentioned, the colors used for the masking layer and the adhesive protective layer are stoving colors. The masking layer and the adhesive protective layer are preferably - possibly with the interposition of a drying measure, e.g. B. an infrared drying at about 150 ° C - printed together and then baked together. If single-pane safety glass or other toughened glass panes are used, they can be burned in as part of the toughening process.

0011In particular, the invention can be implemented in various ways. In the case of the glass unit without opto-coating, the masking layer and the adhesive protective layer can be arranged on the inside or outside of the glass pane (s) of the glass unit. If, on the other hand, the glass unit is designed as a single-pane safety glass pane or laminated safety glass pane with an opto-coating, in one embodiment of the invention the opto-coating is arranged on the inside of the glass unit, the inside also carrying the masking layer and the adhesive protection layer applied thereon. Inside means the surface facing away from the atmosphere. However, in the embodiment as a single-pane safety glass pane or laminated safety glass pane, there is also the possibility of arranging the opto-coating on the outside of the glass unit, the opposite side being able to carry the masking layer and the adhesive protective layer applied thereon.

0012It is within the scope of the invention to use an insulating glass unit as the glass unit. If it is an insulating glass unit with an outer pane, inner pane, space between the panes and spacers at the edge between the outer pane and inner pane, the invention teaches that the outer pane preferably has the opto-coating in its translucent area in its translucent area and the spacer with the aid of the adhesive on the adhesive protective layer connected, which in turn is applied to the masking layer, is equipped with the composite surface in the edge area on the outer pane towards the space between the panes. But you can also make the arrangement so that the inner pane has the opto-coating in its translucent area towards the space between the panes, the spacer being connected with the aid of the adhesive to the adhesive protective layer, which in turn is applied to the masking layer, with the composite surface on the outer pane is equipped towards the space between the panes. There is also the possibility of combining the two measures described last, that is to say to apply an optical coating both on the inside of the outer pane and on the inside of the inner pane. The space between the panes can be filled with air or with a gas other than air, e.g. B. with sulfur hexafluoride, krypton, argon or mixtures thereof.

0013The invention is of particular importance for embodiments in which a material based on polysulfide or polyurethane is used as the adhesive.

0014The teaching of the invention leads in the visible spectral range to the desired leveling of the outside view of the glass unit. This is particularly the case when using structural glazing, e.g. B. in facade cladding. However, the glass units according to the invention can also be used as windows, where they are not only exposed to the light incident from the outside, but also at least temporarily from the light which illuminates the room in front of which the windows are located.

0015In the following, the invention will be explained in more detail with reference to a drawing showing only one embodiment. They show a schematic representation<ul id="ul0001" list-style="none"><li>1 shows a section through a glass unit according to the invention,</li><li>2 shows another embodiment of the object of FIG. 1,</li><li>Fig. 3 shows a section through a glass unit according to the invention, which is designed as an insulating glass unit and</li><li>Fig. 4 shows a section through an insulating glass unit which is mounted as a facade panel.</li></ul>

0016The glass units 1 shown in the figures are equipped with an optical coating 2 which has a defined reflection characteristic in the visible spectral range. As usual, this opto-coating 2 is extremely thin. It is, for example, physically, in particular with the aid of magnetron sputtering or chemically e.g. B. applied pyrolytically. The glass units 1 always have an opaque area 3 which is free of the opto-coating 2. This means that the opto-coating 2 is not attached in the opaque area 3 or is destroyed or removed.

0017The opaque area 3 carries a masking layer 4 printed on by screen printing, which has admixed dyes in a matrix and which imparts to the opaque area 3 a reflection characteristic which at least approximately matches that of the opto-coating 2 in the visible spectral range. At least approximately means that the color and the reflectance of the opto-coating 2 and the opaque area 3 do not differ significantly in the incident light when the finished glass unit is inspected by eye. An opaque adhesive protective layer 5 made of a black enamel paint has been applied to the masking layer 4 by means of screen printing. In the area of ​​the composite surface, which here corresponds to the opaque area 3, an adhesive 6 which is sensitive to the action of light is applied to the adhesive protective layer 5. - All layers were drawn excessively thick.

00181, the opto-coating 2 is arranged on the inside of the glass unit 1 and the inside also carries the masking layer 4 with the adhesive protective layer 5 applied thereon. In FIG. 2 it can be seen that the opto-coating 2 is arranged on the outside of the glass unit 1 and that the opposite side carries the masking layer 4 and the adhesive protective layer 5 applied thereon.

00193 shows a section of a glass unit 1 according to the invention, which is designed as an insulating glass unit. The outer pane 7, the inner pane 8, the pane intermediate space 9 and the spacer 10 at the edge between the outer pane 7 and the inner pane 8 can be seen. The outer pane 7 has the opaque region 3 which at the same time faces the pane intermediate space 9 and forms the composite surface . It can be seen that the spacer 10 is connected with the aid of an adhesive 6 to the adhesive protective layer 5, which in turn is applied to the masking layer 4 as described. The adhesive 6 which connects the outer pane 7 and the inner pane 8 can also be different from the adhesive which connects the spacer 10 to the panes 7, 8. - It goes without saying that the glass unit 1 can be connected in various ways with associated components, as a facade panel as indicated in FIG. 4. Fig. 4 shows a section through an insulating glass unit which is designed as a facade panel and is attached to a frame structure 11. Blocking elements 12 are also provided here.

0020Printing inks which can be used in the context of the invention are known to the person skilled in the art. You are e.g. B. described in references EP 0 300 300 A1 and DE 34 33 408 A1. These colors are e.g. B. applied as described in reference EP 0 535 474 A1. But it is also possible to use other common methods such. B. by means of pressure rollers or the like. The printing inks are always so-called ceramic inks that are burned in. In this respect, a ceramic bond or enamel bond with the surface of the glass panes is created. The thickness of the masking layer 4 is set up so that it fulfills its coloring function. For the adhesive protective layer it applies that its thickness and the material used are set up in such a way that it fulfills its adhesive protective function. The thicknesses are in the range of 0.005 to 0.05 mm, preferably 0.01 to 0.02 mm.

0021An exemplary embodiment is described below with reference to the embodiment according to FIG. 3:

0022An insulating glass unit with an 8 mm thick outer pane 7, a pane 9 between 12 mm and an outer pane 8 with a thickness of 4 mm has a thermal protection layer with the following layer structure as the optical coating 2: SnO₂/ ITO d = 35 nm, silver d = 8 nm, NiCr d = 0.5 nm, ITO / SnO₂ d = 35 nm. As shown in FIG. 3, the optical coating 2 can be arranged on the inside of the outer pane 7 (item 2) or else on the outside of the inner pane 8. The masking layer 4 is applied to position 2. It consists of a commercially available enamel paint with suitable color coordinates or is made by mixing commercially available printing inks. In the present case, the ink consists of several 600,000 series printing inks from Cookson Mathey, which are mixed so that a RAL value of 7010 is achieved. These colors are enamel colors with ≥ 30% by weight of lead oxide and approx. 20% by weight of pigment (lead borosilicate frits). A customary opaque adhesive protective layer made of black enamel paint which is opaque to UV radiation and visible light is applied to the masking layer.

0023If such an insulating glass unit is glazed in a structural glazing system and the space in the building is only slightly or not illuminated at all, then the masking layer 4 and the opto-coating 2 show a similar reflection characteristic when the sky is overcast, i.e. the masking layer 4 and the opto-coating 2 are seen from the outside hardly distinguishable. If, on the other hand, a black adhesive protective layer without a masking layer is used in a conventional manner, then this can be clearly distinguished from the opto-coating 2.

0024The reflection behavior was also measured on such an element.

0025Measuring device: Miniscan MS7S 4000 L, light type D65 / 10 ° field of view, diffuse illumination<tables id="tabl0001" num="0001"><img file="EP0807611A1_D0004.tif" /></tables> Measurements according to DIN 6174 and 5033.

0026It can be seen that both with the arrangement of the opto-coating 2 on the outer pane 7 (item 2) and on the inner pane 8 (item 3), the reflection characteristics for the opaque area and for the translucent area are suitable for the glass unit according to the invention with a marking layer 4 and opaque adhesive protective layer 5 differ only slightly, while both L ∗ and a ∗ and b ∗ show clear deviations in the conventional design only with a black adhesive protective layer.