Process for obtaining an insulating glazing

Abstract

A process for obtaining an insulating glazing including first and second glass sheets that are held parallelly spaced apart with a transparent glass spacer adhesively bonded to the periphery of the glass sheets to make a gas-filled interlayer space, includes providing the spacer that is substantially parallelepipedal and including two rough faces opposite one another, and two smooth faces opposite one another, assembling the spacer between the glass sheets so that each rough face of the spacer is positioned close to an edge, and against an inner face of each glass sheet, the interstitial width between the rough faces of the spacer and the inner faces of the glass sheets being less than 0.01 mm, depositing, at the external joint lines between the rough faces and the inner faces, a transparent adhesive, the adhesive moving by capillary action to cover the surface of the rough faces, then curing the adhesive.

Claims

1. A process for obtaining an insulating glazing comprising first and second glass sheets that are held parallelly spaced apart with the aid of at least one transparent glass spacer adhesively bonded to the periphery of said glass sheets so as to make a gas-filled interlayer space, said process comprising: providing said spacer, said spacer being substantially parallelepipedal and comprising at least two rough faces opposite one another, and two smooth faces opposite one another, then assembling said spacer between the glass sheets, so that each rough face of said spacer is positioned close to an edge, and against an inner face of each of said glass sheets, the interstitial width between the rough faces of the spacer and the inner faces of the glass sheets being less than 0.01 mm, then depositing, at external joint lines between the rough faces of the spacer and the inner faces of the glass sheets, a transparent adhesive, said adhesive moving by capillary action so as to cover the surface of said rough faces of the spacer, then curing said adhesive, wherein, at the end of said assembling, the interstitial width between the rough faces of the spacer and the inner faces of the glass sheets is at most 0.01 mm over an entire length of the spacer, and thus over an entire length of the edge of the glass sheet in a vicinity of which the spacer is placed, and wherein the Rz roughness, within the meaning of the ISO 4287:1997 standard, of the rough faces of the spacer is within a range of from 1 to 10 μm.

2. The process as claimed in claim 1, wherein the spacer has two chamfers on the smooth face intended, in the mounted position of the spacer, to form the edge face of the glazing.

3. The process as claimed in claim 1, wherein, during the depositing of the adhesive, the adhesive has a viscosity of between 300 and 900 mPa.s.

4. The process as claimed in claim 1, wherein the adhesive is UV crosslinkable and the curing is carried out by exposure to ultraviolet radiation.

5. The process as claimed in claim 4, wherein the exposure to ultraviolet radiation is carried out from a single side of the assembly.

6. The process as claimed in claim 4, wherein the ultraviolet radiation is derived from light-emitting diodes.

7. The process as claimed in claim 4, wherein the intensity of the ultraviolet radiation emitted by the source is within a range of from 10 to 200 mW/cm.sup.2.

8. The process as claimed in claim 7, wherein the intensity of the ultraviolet radiation emitted by the source is within a range of from 20 to 150 mW/cm.sup.2.

9. The process as claimed in claim 4, wherein a duration of exposure to the ultraviolet radiation is within a range of from 1 to 1000 seconds.

10. The process as claimed in claim 9, wherein the duration of exposure to the ultraviolet radiation is within a range of from 10 to 500 seconds.

11. The process as claimed in claim 1, wherein a difference between the refractive index of the adhesive, after crosslinking, and the refractive index of the glass used for the spacers and the glass sheets, is at most 0.3.

12. The process as claimed in claim 11, wherein the difference between the refractive index of the adhesive, after crosslinking, and the refractive index of the glass used for the spacers and the glass sheets, is at most 0.1.

13. The process as claimed in claim 1, further comprising, prior to providing the spacer, cutting the spacer starting from a glass sheet.

14. The process as claimed in claim 13, wherein the cutting is carried out by scoring-breakage or laser cutting.

15. The process as claimed in claim 1, wherein the Rz roughness, within the meaning of the ISO 4287:1997 standard, of the rough faces of the spacer is within a range of from 2 to 9 μm.

16. The process as claimed in claim 1, further comprising, after said assembling and prior to said depositing, determining, with a calibrated thickness gauge or block, whether the interstitial width is at most 0.01 mm over the entire length of the spacer.

17. The process as claimed 16, wherein the calibrated thickness gauge or block has a thickness of 0.01 mm and, when the calibrated thickness gauge or block is insertable in the interstitial width at a position along the entire length of the spacer, the method further comprises reducing the interstitial width at said position with a clamp.

18. An insulating glazing obtained by the process as claimed in claim 1, said glazing comprising said first and second glass sheets that are held parallelly spaced apart with the aid of said at least one transparent glass spacer adhesively bonded at the periphery of said glass sheets so as to make a gas-filled interlayer space.

19. The insulating glazing as claimed in claim 18, which comprises two of said transparent glass spacers adhesively bonded to the entire length of the long edges of the glass sheets, and to non-transparent spacers adhesively bonded to the entire length of the short edges of the glass sheets.

20. The insulating glazing as claimed claim 18, which has at least one of the following performances, after aging: a moisture penetration index measured under the conditions of the EN 1279-6 standard of at most 5%, a moisture penetration index measured under the conditions of the EN 1279-2 standard of at most 15%, a gas leakage rate measured under the conditions of the EN 1279-3 standard of at most 1.0% per year.

21. A climate-controlled unit comprising at least one insulating glazing as claimed in claim 18.

Description

(1) The following examples and FIGURE illustrate the invention in a nonlimiting manner.

(2) FIG. 1 illustrates a partial cross-sectional view of an assembly of glass sheets and of intended transparent spacer, at the end of the assembling step.

(3) Apart from the adhesive, the various constituents of the final glazing are represented in this FIGURE, which may therefore also represent a partial cross section of a glazing obtained according to the invention.

(4) The glazing 1 is obtained by assembling first and second glass sheets 2 and 3, held parallelly spaced apart with the aid of a transparent glass spacer 4 so as to make an interlayer space 5, which will be filled with gas.

(5) The spacer 4 is substantially parallelepipedal, with an overall rectangular cross section, if the presence of the chamfers 45 and 46 is disregarded. The spacer 4 comprises two rough faces 41 and 42 that are opposite one another and also two smooth faces 43 and 44 that are also opposite one another.

(6) The spacer 4 was obtained by cutting from a sheet of float glass, the rough faces 41 and 42 corresponding to the cutting faces (optionally after a subsequent polishing) and the smooth faces 43 and 44 to the original faces of the glass sheet.

(7) The assembling is carried out so that each rough face, respectively 41 and 42, is placed against an inner face, respectively 21 and 31, of the glass sheets 2 and 3, close to an edge. The smooth face 43 is therefore on the outer edge face of the glazing, and the smooth face 44 is turned toward the interlayer space.

(8) During the assembling step, clips (not represented), are preferably positioned in certain zones of the edge of the assembly in order to exert pressure on the glass sheets. The assembly is preferably formed horizontally, as represented in the FIGURE. The interstitial width is thus influenced by the Rz roughness of the rough faces and by the vertical pressure due to gravity and to the clamping exerted by the clips.

(9) In FIG. 1, the glass sheets 2 and 3 are also chamfered.

(10) The assembly forms external joint lines 24 and 34 between the rough faces 41 and 44 and the inner faces 21 and 31 of the glass sheets. It is at these joint lines that the adhesive is deposited, for example by means of a syringe. The presence of chamfers makes it possible to facilitate this deposition step.

(11) An assembly such as the one represented in FIG. 1 was formed from square glass sheets with sides of 10 cm and 10 cm long transparent glass spacers.

(12) The spacers had a rectangular cross section (thickness of 10 mm and width of 13 mm) with a chamfer.

(13) Before assembly, the rough faces of the spacers and the zone of the inner faces of the glass sheets intended to come into contact with the spacers were coated with an adhesion primer. The primer was deposited in two steps, firstly a deposition of silica by pyrolysis by means of a torch, then a deposition of a Pyrosil® primer sold by Bohle.

(14) Clips were positioned in order to hold the assembly in place during the steps of depositing and curing the adhesive.

(15) For the comparative examples, the interstitial width was imposed by the interposition of calibrated thickness gauges positioned at the ends of the assembly. For the examples according to the invention, no thickness gauge was positioned in the assembly, but verification using a 0.01 mm thick calibrated gauge made it possible to confirm that the interstitial width was less than 0.01 mm. Over the length of the spacer, it was indeed impossible, without forcing, to insert the gauge into the entire thickness of the spacer.

(16) Two types of spacers were used. Spacer 1 has an Rz roughness of 5 to 6 μm, spacer 2 an Rz roughness of around 4 μm.

(17) The adhesive (Verifix LV 740 sold by Bohle) was then deposited using a syringe at the external joint lines between the rough faces of the spacer and the inner faces of the glass sheets.

(18) The assembly was then subjected, in the adhesive bonding zone, to exposure to ultraviolet radiation using two types of radiation sources: a neon discharge lamp, having an emission spectrum that has a broad band ranging from 320 to 400 nm and centered on the wavelength of 360 nm, or an LED lamp having a narrow emission spectrum between 360 and 390 nm.

(19) The lamps were located 1 cm from the assembly.

(20) The glazings obtained were subjected to accelerated aging in a wet environment, at a temperature of 58° C. for a relative humidity of greater than 95%.

(21) The table below presents, for each of the tests, the type of spacer (1 or 2), the interstitial width (noted i and expressed in mm), the nature of the source, the intensity of the source (noted I, in mW/cm.sup.2), the exposure duration (noted d and expressed in seconds), and also the results of the aging test.

(22) These results consist of an initiation time (noted t and expressed in hours) and a qualitative score (noted F, unitless). The score F is given after visual examination of the adhesive bonding zone. A score of 5 or less indicates an absence of cracking or very minor cracking. The higher the score, the more the adhesive bonding zone has large cracks. The initiation time corresponds to the aging time starting from which the samples obtain a score of 5.

(23) TABLE-US-00001 TABLE 1 Spc. i (mm) Source I (mW/cm.sup.2) d (s) t (h) F C1 1 0.03 Neon 14 300 74 7 C2 1 0.09 Neon 14 300 40 12 C3 1 0.15 Neon 14 300 48 13 C4 1 0.18 Neon 14 300 48 10 C5 1 0.18 LED 75 180 72 12 1 1 <0.01 Neon 14 300 >408 1 2 1 <0.01 LED 75 180 408 4 3 2 <0.01 LED 75 180 >408 0

(24) The comparison between the examples according to the invention 1 to 3 and the comparative examples C1 to C5 shows that the choice of an interstitial width of less than 0.01 mm makes it possible to prevent, to a large extent, the appearance of cracks after wet aging.

(25) Other aging tests were also carried out on glazings obtained according to the invention or not obtained according to the invention.

(26) Tests of moisture penetration after a short aging cycle were carried out under the conditions of the EN 1279-standard, and in the case of an implementation of the invention in accordance with that of example 3, the moisture penetration index I was less than 5%. On the other hand, in an implementation in which the interstitial width was not less than 0.01 mm, the index I was generally greater than 10%, or even 20%.

(27) Tests of moisture penetration after a long aging cycle (EN 1279-2 standard) were also performed. In the case of manufacture in accordance with the invention (example 3), the moisture penetration index was at most 15%.

(28) Finally, tests for measuring the gas leakage after aging were carried out in accordance with the EN 1279-3 standard. In the case of manufacture in accordance with the invention (example 3), the gas leakage rate L.sub.i was at most 0.4% per year.