PANE WITH THERMAL-RADIATION-REFLECTING COATING AND FASTENING OR SEALING ELEMENT ATTACHED THERETO

Abstract

A pane for separating an interior from an external environment, at least including a substrate, and a thermal-radiation-reflecting coating on the interior-side surface of the substrate is disclosed. The coating has at least one functional layer containing a transparent conductive oxide and a topmost layer containing silicon dioxide, and a polymeric fastening or sealing element on the thermal-radiation-reflecting coating.

Claims

1. A pane for separating an interior from an external environment, comprising: a substrate; a thermal-radiation-reflecting coating on the interior-side surface of the substrate, the thermal-radiation-reflecting coating having at least one functional layer containing a transparent conductive oxide and a topmost layer containing silicon dioxide; and a polymeric fastening or sealing element on the thermal-radiation-reflecting coating.

2. The pane according to claim 1, wherein the polymeric fastening or sealing element is arranged in direct contact with the thermal-radiation-reflecting coating.

3. The pane according to claim 1, wherein an opaque masking print is arranged between the thermal-radiation-reflecting coating and the fastening or sealing element.

4. The pane according to claim 1, wherein the polymeric fastening or sealing element comprises a sealing lip, an adhesive bead for fastening the pane or an adhesive for fastening an attachment part on the pane.

5. The pane according to claim 1, wherein the fastening or sealing element contains polyurethane, polyolefin, polysulfide, poly-epoxy, rubber such as natural rubber, nitrile rubber (NBR), styrene butadiene rubber, butadiene acrylonitrile rubber, ethylene propylene diene rubber, silicone rubber such as RTV(room-temperature-vulcanizing) silicone rubber, HTV(high-temperature-vulcanizing) silicone rubber, peroxide-vulcanising silicone rubber, or addition-vulcanising silicone rubber, polyacrylate, styrene/butadiene block copolymer (SBS), ethylene propylene diene rubber (EPDM), and/or a thermoplastic elastomer (TPE).

6. The pane according to claim 1, wherein the fastening or sealing element contains heat-curing polymers, moisture-curing polymers, or UV-curing polymers.

7. The pane according to claim 1, wherein the substrate contains glass.

8. The pane according to claim 1, wherein a primer is applied between the thermal-radiation-reflecting coating and the fastening or sealing element.

9. The pane according to claim 8, wherein the primer contains polyisocyanate, reactive silane, methacrylate, and/or polyurethane.

10. The pane according to claim 1, wherein the functional layer contains at least fluorine-doped tin oxide, antimony-doped tin oxide, and/or indium tin oxide.

11. The pane according to claim 1, wherein the topmost layer has a thickness of 20 nm to 150 nm.

12. A method for producing a pane with a thermal-radiation-reflecting coating and a polymeric fastening or sealing element, comprising: (a) applying a thermal-radiation-reflecting coating on the interior-side surface of a substrate, wherein said coating has at least one functional layer containing a transparent conductive oxide and a topmost layer containing silicon dioxide; and (b) attaching a polymeric fastening or sealing element to said coating.

13. The method according to claim 12, wherein between the process steps (a) and (b), a primer is applied on said coating.

14. The method according to claim 12, wherein said coating is treated between the process steps (a) and (b) with a cleaning solution.

15. A method for using a pane for separating an interior from an external environment; comprising: providing a pane for separating according to claim 1; and using the pane for separating as a vehicle pane or a component of a vehicle pane.

16. The method according to claim 15, wherein the component of a vehicle is a motor vehicle roof panel.

17. The method according to claim 14, wherein the cleaning solution contains a silane, a surfactant, an alcohol, a ketone, or mixtures thereof.

18. The pane according to claim 6, wherein the fastening or sealing element contains moisture-reactive hot-melt adhesives, the moisture-reactive hot-melt adhesives including polyurethane-prepolymers, polyesters, polyolefins, polyamides, or mixtures or copolymers thereof, or hot-curing adhesives, such as polyurethanes, silicones, polyacrylates, and poly-epoxies (epoxy resins) or mixtures thereof.

19. The pane according to claim 10, wherein the functional layer has a thickness of 40 nm to 200 nm.

20. The pane according to claim 11, wherein the topmost layer has a thickness of 40 nm to 100 nm.

Description

[0061] They depict:

[0062] FIG. 1 a plan view of the interior-side surface of an embodiment of the pane according to the invention with a thermal-radiation-reflecting coating,

[0063] FIG. 2 a cross-section along A-A through the pane of FIG. 1,

[0064] FIG. 3 an enlarged view of the detail Z of FIG. 2,

[0065] FIG. 4 an enlarged view of the detail Z of another embodiment of the pane according to the invention,

[0066] FIG. 5 a cross-section through a substrate with an embodiment of the thermal-radiation-reflecting coating according to the invention,

[0067] FIG. 6 a detailed flowchart of two embodiments of the method according to the invention, and

[0068] FIG. 7 a diagram of the level of reflection of coated panes with different functional layers and different topmost layers.

[0069] FIG. 1, FIG. 2, and FIG. 3 depict in each case a detail of a pane according to the invention. The pane is the roof panel of a motor vehicle and is implemented as a laminated pane (composite pane). It comprises a substrate 1 according to the invention, which functions as an inner pane, and an outer pane 7, which are bonded to one another via a thermoplastic intermediate layer 8. The outer pane 7 and the substrate 1 are made of soda lime glass and and have, in each case, a thickness of 2.1 mm. The thermoplastic intermediate layer 8 is implemented as a 0.76-mm-thick film made of PVB. The roof pane has, as customary in the automotive sector, a curvature.

[0070] The surface of the substrate 1 facing away from the outer pane 7 is the interior-side surface i of the substrate 1 and of the roof panel. It is intended to face the vehicle interior in the installed position. The interior-side surface i is provided over its entire surface with a thermal-radiation-reflecting coating 2. The coating 2 includes a functional layer based on indium tin oxide (ITO) and has as its topmost layer a layer based on SiO.sub.2. By means of the arrangement on the interior-side surface i, the coating 2 acts as a so-called low-E coating.

[0071] The topmost layer according to the invention enables direct attachment of a polymeric fastening or sealing element 3. The removal of the coating 2 in the region of the fastening or sealing element 3 before its attachment can, consequently, advantageously be omitted. In the exemplary embodiment, the surface i with the coating 2 is pretreated with a primer 4, and the fastening or sealing element 3 is implemented as a sealing lip extruded thereon. The sealing lip is cured directly on the pane surface and is attached on the pane via no adhesive other than the primer. The sealing lip protrudes beyond the side edge of the pane and, after installation in the vehicle body, seals the gap between the pane and the body, by which means, in particular, driving noises can be reduced.

[0072] FIG. 4 depict a detail of an alternative embodiment of the pane according to the invention. Here, the fastening or sealing element 3 is not attached directly on the coating 2. Instead, an opaque masking print 5 made of a black enamel is applied on the coating 2, as is customary in the edge region of motor vehicle panes. The fastening or sealing element 3 is, in turn, attached via a primer 4 on the masking print 5. Here, the advantage also resides in the topmost layer based on SiO.sub.2, which enables the printing-on of the coating 2.

[0073] FIG. 5 depicts an exemplary embodiment of a substrate 1 with a thermal-radiation-reflecting coating 2 according to the invention. The coating 2 is a stack of thin layers, consisting, starting from the substrate 1, of an adhesive layer 2c, a functional layer 2a, a barrier layer 2d, and a topmost layer 2b. The layer sequence with exemplary materials and layer thicknesses is presented in Table 1.

TABLE-US-00001 TABLE 1 Reference character Material Thickness 2b 2 SiO.sub.2:Al 70 nm 2d Si.sub.3N.sub.4:Al 10 nm 2a ITO 120 nm 2c SiO.sub.2:Al 35 nm 1 Glass 2.1 mm

[0074] The adhesive layer 2c is made of SiO.sub.2, which is doped with aluminium. It improves the adhesion of the layers applied thereabove on the substrate 1. The functional layer 2a is made of ITO and has the reflecting properties relative to thermal radiation. The barrier layer 2d it is made of Si.sub.3N.sub.4, which is doped with aluminium. It prevents corrosion of the functional layer 2a during a temperature treatment of the coated pane, as occurs, for example, at the time of bending or laminating the pane. The topmost layer 2b is again made of SiO.sub.2, which is doped with aluminium. The topmost layer 2b acts, on the one hand, as an antireflection layer, which increases the transparency of the coated pane. On the other hand, it enables the direct attachment of a polymeric fastening or sealing element 3 or of an opaque masking print 5.

[0075] FIG. 6 depicts, by way of example, two embodiments of the method according to the invention.

[0076] FIG. 7 depicts simulations of the level of reflection RLc of thermal-radiation-reflecting coatings 2 as a function of the functional layer 2a and the topmost layer 2b. The simulations compare the antireflective action of the topmost layers 2b made of Si.sub.3N.sub.4 and SiO.sub.2. Functional layers 2a based on silver are effectively antireflective by topmost layers 2b based on Si.sub.3N.sub.4 up to a thickness of approx. 50 nm (FIG. 7c). From the prior art, it is known that a topmost layer based on Si.sub.3N.sub.4 enables direct attachment of polymeric fastening or sealing elements 3. However, it is clear from the simulations that such a topmost layer 2b based on Si.sub.3N.sub.4 in connection with functional layers 2a based on TCOs does not result in effective antireflectionthe topmost layers 2b based on SiO.sub.2 according to the invention are suitable for this (FIG. 7a,b).

EXAMPLE 1ADHESION PROPERTIES

[0077] Test panes according to the invention and comparative panes were produced with a thermal-radiation-reflecting coating 2 with a functional layer 2a made of ITO and a sealing lip attached thereon as sealing element 3. The coating 2 on the test panes according to the invention differed from the coating 2 on the comparative panes only through the material of the topmost layer 2b: according to the invention, SiO.sub.2 was used here, TiO.sub.2 in the comparative panes. The panes with the sealing element 3 were artificially aged by temperature, moisture, and salt treatment. Then, the adhesion of the sealing element 3 was verified by means of a manual peel test: the sealing element 3 was cut down to the substrate 1 and then peeled off along its direction of extension. Then, the fracture pattern was evaluated per DIN EN ISO 10365. Cohesive breakage (breakage within the sealing element 3) is acceptable, whereas adhesive breakage (release of the entire sealing element 3 from the coating 2) is unacceptable.

[0078] The results are presented in Table 2. It is clearly discernible that the topmost layer 2b according to the invention resulted in all cases in good adhesive behaviour, whereas that was the case in only one fourth of the cases with the comparative panes.

TABLE-US-00002 TABLE 2 Cohesive breakage Adhesive breakage Topmost layer 2b (acceptable) (unacceptable) SiO.sub.2 100% 0% TiO.sub.2 25% 75%

[0079] Thus, not all topmost layers 2b suitable as antireflection layers are suitable for direct application of a polymeric sealing element 3. This is enabled by the selection according to the invention of the topmost layer 2b based on SiO.sub.2. This result was unexpected and surprising for the person skilled in the art.

EXAMPLE 2PRINTABILITY

[0080] Test panes according to the invention and comparative panes were produced with a thermal-radiation-reflecting coating 2 with a functional layer 2a made of ITO and a black enamel printed thereon as an opaque masking print 5. The coating 2 on the test panes according to the invention differed from the coating 2 on the comparative panes only by the material of the topmost layer 2b: according to the invention, SiO.sub.2 was used here, in the comparative pane, Si.sub.3N.sub.4.

[0081] The enamel was applied on the coated panes at different temperatures. Then, the masking print 5 was evaluated visually (surface and along a fracture edge). The observations are summarized in Table 3.

TABLE-US-00003 TABLE 3 Topmost layer 2b T = 615 C. T = 650 C. T = 700 C. SiO.sub.2 Good result Good result Good result Si.sub.3N.sub.4 Very high porosity High porosity and Formation of large and coarseness, coarseness, poor blisters, detachment very poor sintering sintering of the enamel

[0082] The results show that the topmost layer 2b made of SiO.sub.2 according to the invention is compatible with the opaque masking print 5, but the known topmost layer made of Si.sub.3N.sub.4 is not. This result was unexpected and surprising for the person skilled in the art.

LIST OF REFERENCE CHARACTERS

[0083] (1) substrate [0084] (2) thermal-radiation-reflecting coating [0085] (2a) functional layer of 2 [0086] (2b) topmost layer of 2 [0087] (2c) adhesive layer of 2 [0088] (2d) barrier layer of 2 [0089] (3) fastening or sealing element [0090] (4) primer [0091] (5) opaque masking print [0092] (7) outer pane [0093] (8) thermoplastic intermediate layer [0094] (i) interior-side surface [0095] A-A section line [0096] Z enlarged detail