COATED GLAZING

Abstract

The disclosure involves a coated glazing, a method of manufacturing the glazing and the use of a layer based on silica and/or an organo silica deposited on a glazing to achieve a coefficient of kinetic friction between an exterior surface of the layer based on silica and/or an organo silica and a contact surface wiping device that does not substantially change between a dry state and a wet state of the surfaces. Also disclosed is a glazing suitable for combination with a wiping device, the combination of said glazing with a wiping device and the use of the glazing to facilitate a reciprocating motion of a part of a wiping device and/or to facilitate a tilting and/or flipping of a part of a wiping device.

Claims

1. A coated glazing comprising: a transparent substrate directly or indirectly coated on a major surface thereof with at least one layer based on silica and/or an organo silica, wherein the at least one layer based on silica and/or an organo silica has a thickness of at least 5 nm but at most 45 nm, and wherein the at least one layer based on silica and/or an organo silica is obtained by partially or completely converting at least one layer based on one or more silazane.

2. The coated glazing according to claim 1, wherein said at least one layer based on silica and/or an organo silica has a thickness of at least 10 nm, but at most 40 nm.

3. The coated glazing according to claim 1, wherein the coefficient of kinetic friction between an exterior surface of the layer based on silica and/or an organo silica and a contact surface of a wiping means, in a wet and/or dry state, at a force of 10-110 mN and at a speed of 600 mm/s, is at least 0.1, but at most 5.

4. The coated glazing according to claim 3, wherein the coefficient of kinetic friction between an exterior surface of the layer based on silica and/or an organo silica and a contact surface of a wiping means, in a wet and/or dry state, at a force of 10-110 mN and at a speed of 600 mm/s, is at least 0.4, but at most 0.8.

5. The coated glazing according to claim 1, wherein the coefficient of kinetic friction between an exterior surface of the layer based on silica and/or an organo silica and a contact surface of a wiping means does not change between a wet and a dry state by more than 50%.

6. The coated glazing according to claim 1, wherein the transparent substrate is directly or indirectly coated with an underlayer, wherein said underlayer is located between said major surface of the transparent substrate and said at least one layer based on silica and/or an organo silica.

7. The coated glazing according to claim 6, wherein the underlayer comprises at least one layer based on a transparent conductive coating (TCC).

8. A method of manufacturing a coated glazing comprising: depositing at least one layer based on one or more silazane on a major surface of a transparent substrate, partially or completely converting the at least one layer based on one or more silazane to at least one layer based on silica and/or an organo silica, and wherein the at least one layer based on silica and/or an organo silica has a thickness of at least 5 nm but at most 45 nm.

9. The method according to claim 8, wherein said at least one layer based on one or more silazane is deposited by spin coating, slot die coating, spraying such as flame spray coating, roller coating, dipping, and/or printing.

10. The method according to claim 8, wherein said partial or complete conversion of the at least one layer based on one or more silazane to at least one layer based on silica and/or an organo silica comprises treating the transparent substrate with heat, UV radiation and/or IR radiation after depositing the at least one layer based on one or more silazane.

11. (canceled)

12. A glazing suitable for combination with a wiping means, comprising: a transparent substrate having a major surface, wherein, when combined with said wiping means, said major surface contacts said wiping means, wherein, in use, said wiping means wipes a first area of said major surface as a result of a part of said wiping means moving between a first position and a second position in a reciprocating motion, wherein, when said part of said wiping means is in the first position and/or when said part of said wiping means is in the second position, said part contacts a second area of said major surface, and wherein the coefficient of kinetic friction between a contact surface of said part of said wiping means and said major surface located in at least part of said second area of said major surface is higher than the coefficient of kinetic friction between a contact surface of said part of said wiping means and said major surface located in at least part of said first area that does not occupy the same area as said at least part of said second area.

13. The glazing according to claim 12, wherein the transparent substrate is directly or indirectly coated on at least a portion of the major surface thereof with at least one layer, such that, references to said at least one portion of the major surface of the transparent substrate are to be construed as references to an external surface of said at least one layer.

14. The glazing according to claim 13, wherein said at least one layer coats at least a portion of the first area, preferably said at least one layer coats substantially all or all of the first area.

15. The glazing according to claim 13, wherein said at least one layer coats substantially all or all of said at least part of said second area.

16. The glazing according to claim 15, wherein said at least one layer coats substantially all or all of said second area.

17. The glazing according to claim 15, wherein the composition of the at least one layer in the area of at least part of or all of the second area differs from the composition of the at least one layer outside the area of at least part of or all of the second area.

18. The glazing according to claim 15, wherein at least part of or all of the second area is coated with a further layer, deposited on the at least one layer.

19. The glazing according to claim 18, wherein the composition of the further layer in the area of at least part of or all of the second area differs from the composition of the at least one layer outside the area of at least part of or all of the second area.

20. The glazing according to claim 13, wherein said at least one layer is based on silica and/or an organo silica.

21. The glazing according to claim 20, wherein the at least one layer based on silica and/or an organo silica is obtained by partially or completely converting at least one layer based on one or more silazane.

22. The glazing according to claim 30, wherein said further layer based on silica and/or an organo silica is obtained by deposition using a precursor based on one or more of silane, tertraethyl orthosilicate (TEOS), and/or hexamethyldisiloxane (HMDSO).

23. The glazing according to claim 12, wherein the coefficient of kinetic friction between a contact surface of said part of said wiping means and said major surface located in at least part of said second area of said major surface is 10% higher, than the coefficient of kinetic friction between a contact surface of said part of said wiping means and said major surface located in at least part of said first area that does not occupy the same area as said at least part of said second area.

24. The glazing according to claim 13, wherein said at least one layer has a thickness of at least at least 5 nm, but at most 100 nm.

25. The glazing according to claim 12, wherein the coefficient of kinetic friction between the major surface located in at least part of said first area of said major surface and a contact surface of a wiping means, in a wet and/or dry state, at a force of 10-110 mN and at a speed of 600 mm/s, is at least 0.1, but at most 1.

26. The glazing according to claim 12, wherein the coefficient of kinetic friction between the major surface located in at least part of said first area of said major surface and a contact surface of a wiping means, does not change between a wet and a dry state by more than 50%.

27. The coated glazing according to claim 1, wherein the coated glazing is a vehicle glazing.

28. The combination of the glazing according to claim 12 with a wiping means.

29. Use of the glazing of claim 12 to facilitate a reciprocating motion of a part of a wiping means and/or to facilitate a tilting and/or flipping of a part of a wiping means.

30. The glazing according to claim 18, wherein said further layer is based on silica and/or an organo silica.

31. The glazing according to claim 30, wherein said further layer based on silica and/or an organo silica is obtained by partially or completely converting at least one layer based on one or more silazane and has a thickness of at least 5 nm, but at most 100 nm.

Description

[0066] The invention will now be further described by way of the following specific embodiments, which are given by way of illustration and not of limitation, with reference to the accompanying drawings in which:

[0067] FIG. 1 is a schematic plan view of a combination of a glazing of the present invention and two wipers that are configured to move in parallel; and

[0068] FIG. 2 is a schematic plan view of a combination of a glazing of the present invention and two wipers that are configured to move in opposing directions.

[0069] FIG. 1 shows a vehicle glazing 1, specifically a windscreen, according to the present invention combined with a wiping means 2. Glazing 1 is coated on an external major surface 3 with a layer of silica that covers the entirety of surface 3. Wiping means 2 comprises two wiper blades 4, two wiper arms 5, two rotatable shafts 6 and a motor (not shown). Each wiper blade 4 is attached to a first end of a different wiper arm 5. Each wiper arm 5 is attached at an opposing second end to a different rotatable shaft 6. The two wiper blades 4 both contact surface 3.

[0070] In use, the motor rotates the shafts 6 such that their motion is synchronised, causing wiper arms 5 and consequently wiper blades 4 to move in parallel/unison. Shafts 6 rotate alternately in a clockwise and in a counter-clockwise sense which causes the wiper blades 4 to move in a reciprocating motion over surface 3, wiping first area 7. The wiper blades 4 wipe first area 7 of said major surface 3 by moving between a first position and a second position. The hatched areas in FIG. 1 represent the surface 3 of the glazing 1 in the regions of these first and second positions which together comprise second area 8. The silica layer at the surface 3 in second area 8 differs from the rest of the silica layer in first area 7 in that it is deposited using an organo silane precursor. This arrangement ensures a greater coefficient of kinetic friction between the surface 3 in the second area 8 and the rubber of the wiper blades 4, than between the surface 3 in the rest of the first area 7 and said rubber. This arrangement encourages the tilting and/or flipping of the wiper blades 4 when they change direction i.e. when the wiper blades 4 are in the first or second position, contacting second area 8. The coefficient of friction between surface 3 in first area 7 (including second area 8) and the rubber of the wiper blades 4 does not substantially change between a dry state and a wet state.

[0071] FIG. 2 shows another vehicle glazing 1, specifically a windscreen, according to the present invention combined with an alternative wiping means 2. The reference numerals associated with features in FIG. 1 are also used for corresponding features in FIG. 2. The wiping means 2 of FIG. 2 differs from that of FIG. 1 in that, in use, the motor of the wiping means of FIG. 2 rotates the shafts 6 in opposite directions (clockwise and counter-clockwise), causing wiper arms 5 and consequently wiper blades 4 to move in opposing directions. Again, shafts 6 rotate alternately in a clockwise and in a counter-clockwise sense which causes the wiper blades 4 to move in a reciprocating motion over surface 3, wiping first area 7.

[0072] FIG. 1 and FIG. 2 exemplify two different modes of operation for wiping means and there are of course several other types of wiping means that could be used in combination with the present invention such as single-blade systems, pantograph systems, and complex arc systems.

EXAMPLES

[0073] Four samples of 2.2 mm thick Pilkington Energy Advantage glass were each coated (on the coated side) with a layer of perhydropolysilazane which was then converted to a layer of silica by heating the samples at 200 C. for 1 hr. The silica layers deposited on the four samples had respective thicknesses of 25 nm, 50 nm, 100 nm and 150 nm. These four samples, plus a reference sample of 2.2 mm thick Pilkington Energy Advantage glass that has not been coated or treated, then underwent coefficient of kinetic friction tests.

[0074] The tests were carried out under dry and wet conditions using a Bosch Superplus 24 wiper blade that was cut to a length of 19 mm. A CSM Micro-Combi Tester was used in scratch mode to perform the friction tests and a load of 10-110 mN was applied by the wiper blade upon the coated side of the sample. The tests were performed over a length of 65 mm and at a speed of 600 mm/min.

[0075] For each sample a separate 19 mm wiper blade was glued to a glass disc which was fixed to the end of an indenter holder of the CSM Micro-Combi Tester. Prior to testing, the samples were cleaned using an aerosol solvent spray followed by de-ionised water and finally removal of any debris with a Dust Off aerosol spray. For the wet tests a pool of de-ionised water of approximately 2 ml volume was applied to the sample surface. Five runs were conducted for each test and the results were averaged, using data obtained between 10 and 60 mm of travel avoiding the effects of load variations at the start and end of each test.

TABLE-US-00001 TABLE 1 Coefficient of kinetic friction values, under wet or dry conditions, between a wiper blade and each of five samples, including a reference sample (2.2 mm thick Pilkington Energy Advantage (RTM) glass) and four samples that bear a silica topcoat of differing thicknesses. Coefficient of Kinetic Friction Sample Dry State Wet State Reference (no top silica layer) 1.23 0.75 25 nm silica topcoat 0.44 0.44 50 nm silica topcoat 1.35 0.50 100 nm silica topcoat 2.30 0.50 150 nm silica topcoat 3.22 0.54

[0076] As Table 1 above shows, the sample with a 25 nm thick silica topcoat derived from a layer of perhydropolysilazane exhibited a coefficient of kinetic friction between the surface of the silica topcoat and a contact surface of the wiper blade that does not change between a dry state and a wet state. In contrast, the other tested samples exhibited reductions in the coefficient of kinetic friction upon changing from a dry state to a wet state. Furthermore, the sample with a 25 nm thick silica topcoat exhibits coefficients of friction in the desirable range of 0.4-0.6 which is beneficial in terms of noise reduction, water removal efficiency, and smoothness of travel, resulting in reduced wiper blade erosion and extended lifetime.

[0077] The invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.