Transparent glazing for aircraft, aircraft and production method

Abstract

The invention relates to a transparent glazing (10) for an aircraft, comprising a transparent organic substrate (12) and a transparent solar control coating (14), the transparent glazing (10) having a selectivity greater than or equal to 1.17 and colorimetric coordinates in transmission b* greater than or equal to -0.5 in the CIE L*a*b* space under an illuminant D65 and a reference observer 2°, preferably b* greater than or equal to 0. The invention also relates to an aircraft comprising such a glazing and to a method for manufacturing such a glazing.

Description

DESCRIPTION TITLE: TRANSPARENT GLAZING FOR AIRCRAFT, AIRCRAFT AND MANUFACTURING PROCESS technical field

[0001] This paper concerns transparent aircraft glazing, more specifically transparent aircraft glazing with a solar control function. This paper also concerns a manufacturing process for such glazing. Previous technique

[0002] So-called "solar control" glazing is glazing that limits the heating of vehicles exposed to the sun thanks to properties that limit the flow of energy, particularly Infrared (IR) radiation, passing through it from the outside to the inside without significantly impacting light transmission in the visible spectrum.

[0003] We know of glazing systems composed of stacked thin films that provide this solar control function. This technology can be achieved, for example, by depositing layers of evaporated or sprayed gold, which results in a strong yellow tint. In other embodiments, the layers can be obtained by magnetron deposition as a stack of several thin films. These solutions allow for more neutral tints but are complex to implement, particularly for large substrates and / or those with a pronounced radius of curvature, and can also pose adhesion problems for the coating on organic substrates.

[0004] In the aeronautical field, aircraft glazing made of organic materials containing particles that provide solar control is also known. These particles are directly incorporated into the organic material forming the glazing. This technology is relatively expensive and not very flexible.

[0005] It is also possible to manufacture aircraft glazing with a solar control function by incorporating particles that provide this function into the adhesive intermediate layer of laminated glass. However, this technology is only suitable for glazing requiring lamination for reasons other than solar control. In the case of monolithic glazing, the use of laminated glazing significantly increases the cost and mass of the glazing.

[0006] Therefore, there is a need in the aeronautical field to provide transparent aircraft glazing with reduced mass, reduced cost, easier implementation than known processes, high flexibility, while complying with the certification standards applicable to aircraft. Description of the invention

[0007] The present presentation aims to remedy at least some of these drawbacks.

[0008] To this end, the present exposition relates to a transparent aircraft glazing, according to claim 1, comprising a transparent organic substrate and a transparent solar control coating, the transparent glazing having a selectivity greater than or equal to 1.17 and colorimetric transmission coordinates b* greater than or equal to -0.5 in the CIE L*a*b* space under a D65 illuminant and a 2° reference observer, preferably b* greater than or equal to 0.

[0009] The transparent solar control coating allows absorption in wavelengths in the near-infrared, i.e. between 780-2500 nm, and gives the transparent glazing a selectivity that reduces the undesirable effects of light radiation in the near-infrared without negatively impacting light transmission in the visible spectrum.

[0010] The term "transparent" encompasses transparent glazing, whether colored or not.

[0011] A transparent glazing is a glazing whose turbidity is less than or equal to 5%, preferably less than or equal to 3%, even more preferably less than or equal to 2%, measured according to ASTM D1003-00.

[0012] By "selectivity", s, we mean the ratio between the light transmission, TL, and the solar factor g.

[0013] By “light transmission”, TL, we mean the light transmission, denoted TL, as defined and measured and / or calculated in the standard EN NF 410:2011 under a D65 illuminant.

[0014] By "solar factor", g, it is understood that the solar factor as defined according to the standard EN NF 410:2011 under a D65 illuminant. It is equal to the sum of the direct solar transmittance, TE, and the secondary heat flux, qi.

[0015] By “direct solar transmission”, TE, we mean energy transmission as defined and calculated according to the standard EN NF 410:2011.

[0016] Furthermore, transparent glazing with a b* value as defined above increases aircraft safety. Indeed, such b* values ​​improve pilot visibility in an airplane or helicopter cockpit, for example, and reduce the risk of errors related to cloud failure (false positives) and / or misjudging the distances to and from a cloud located in the aircraft's flight path. It should be noted that solar control glazing is achieved by limiting the transmission of near-infrared radiation, and therefore often also a portion of red light, which naturally tends to result in negative b* values.

[0017] The b* is measured according to ISO / CIE 11664-4:2019 under illuminant D65 (NF EN ISO / CIE 1164-2:2022) and with a reference observer 2° (ISO / CIE 11664-1:2019).

[0018] As non-limiting examples, transparent glazing can be cockpit glazing or airplane or helicopter porthole glazing.

[0019] In some embodiments, the transparent organic substrate is monolithic.

[0020] In some embodiments, the transparent solar control coating is a transparent scratch-resistant coating.

[0021] The coating is considered scratch-resistant when, during a scratch test according to ISO 1518:1992, no scratches appear under a force of 5 N.

[0022] In some embodiments, the transparent solar control coating has a thickness greater than or equal to 1 pm and less than or equal to 15 pm, preferably greater than or equal to 1 pm and less than or equal to 10 pm, even more preferably greater than or equal to 2 pm and less than or equal to 6 pm.

[0023] According to claim 1, the transparent solar control coating comprises nanoparticles dispersed in an organic matrix, inorganic matrix or mixture thereof.

[0024] Nanoparticles enable solar control while ensuring transparency and visibility through the clear glazing.

[0025] By way of non-limiting examples, the matrix may include a compound based on inorganic or hybrid sol-gel, silica sol-gel, acrylate, polyurethane, silicone and / or epoxy.

[0026] In some embodiments, the transparent solar control coating has a nanoparticle content greater than or equal to 1% by mass and less than or equal to 35% by mass, preferably greater than or equal to 1% by mass and less than or equal to 25% by mass, even more preferably greater than or equal to 1% by mass and less than or equal to 20% by mass.

[0027] According to claim 1, the transparent solar control coating comprises a dye.

[0028] In some embodiments, the transparent solar control coating has a colorant content greater than or equal to 0.005% by mass and less than or equal to 4.00% by mass, preferably greater than or equal to 0.010% and less than or equal to 2.00%.

[0029] In some embodiments, the transparent solar control coating has a colorant content greater than or equal to 0.005% by mass and less than or equal to 0.50% by mass, preferably greater than or equal to 0.010% and less than or equal to 0.25%.

[0030] In some embodiments, the nanoparticles are nanoparticles comprising CsxWOs and the dye has an absorption peak between 350 and 550 nm, for example between 450 and 550 nm.

[0031] In some embodiments, the nanoparticles comprise lanthanum hexaboride, indium tin oxide and / or antimony tin oxide.

[0032] In some embodiments, the transparent organic substrate includes acrylic polymethyl methacrylate, polycarbonate.

[0033] By way of non-limiting examples, acrylic polymethyl methacrylate can be cast acrylic polymethyl methacrylate, stretchable acrylic polymethyl methacrylate, stretched acrylic polymethyl methacrylate.

[0034] In some embodiments, the transparent organic substrate has a non-developable surface, the non-developable surface being coated with the transparent solar control coating.

[0035] A surface is developable if at every point of its surface there exists an orientation without curvature.

[0036] In some embodiments, the transparent glazing has a light transmission greater than or equal to 70%, preferably greater than or equal to 75%, even more preferably greater than or equal to 80%.

[0037] In some embodiments, the transparent glazing has a selectivity greater than or equal to 1.20, preferably greater than or equal to 1.30, even more preferably greater than or equal to 1.40.

[0038] In some embodiments, the transparent glazing has a solar factor of less than or equal to 70%.

[0039] This presentation also relates to an aircraft comprising transparent glazing as defined previously.

[0040] This presentation also relates to a manufacturing process for transparent glazing as defined above, the manufacturing process comprising a liquid coating step of the transparent organic substrate with a liquid precursor of the transparent solar control coating.

[0041] Particularly for large windows and / or those with a more or less pronounced curvature, liquid coating allows the transparent solar control coating to be quickly deposited on one side of the transparent organic substrate.

[0042] By way of non-limiting examples, the liquid deposition step can be carried out by spin coating, dip coating, spray coating, flow coating, curtain coating and / or inkjet coating.

[0043] As a non-limiting example, centrifugal coating can be carried out at a speed greater than or equal to 400 rpm and less than or equal to 1500 rpm.

[0044] In some embodiments, the process includes a drying step of the liquid precursor of the transparent solar control coating to obtain the transparent solar control coating.

[0045] In some embodiments, the drying step has a duration greater than or equal to 30 minutes and less than or equal to 4 hours, preferably greater than or equal to 1 hour and less than or equal to 3 hours.

[0046] In some embodiments, the drying step has a holding temperature which is greater than or equal to 70°C and less than or equal to 130°C, preferably greater than or equal to 80°C and less than or equal to 120°C.

[0047] The drying temperature is chosen so as not to deform and / or alter the mechanical properties of the transparent organic substrate.

[0048] In some embodiments, the drying step is assisted by UV or e-beam radiation. Brief description of the drawings

[0049] Other features and advantages of the object of this presentation will emerge from the following description of embodiments, given by way of non-limiting examples, with reference to the attached figures.

[0050] [Fig. 1] Figure 1 is a partial schematic cross-sectional view of a transparent glazing according to one embodiment.

[0051] [Fig. 2] Figure 2 is a flowchart representing the steps of a manufacturing process for transparent glazing according to one embodiment.

[0052] Across all figures, common elements are identified by identical numerical references. Detailed description

[0053] Figure 1 is a partial schematic cross-sectional view of a transparent aircraft glazing unit 10. The transparent glazing unit 10 in Figure 1 is shown as a planar surface. The transparent glazing unit 10 may have a non-developable surface.

[0054] In cross-sectional view, the transparent glazing 10 comprises a transparent organic substrate 12 and a transparent solar control coating 14.

[0055] The transparent glazing 10 is obtained by a manufacturing process 100 comprising a mixing step 102 to obtain a liquid precursor of the transparent solar control coating, a liquid coating step 104 of the transparent organic substrate 12 with the liquid precursor of the transparent solar control coating and a drying step 106 of the liquid precursor of the transparent solar control coating to obtain the transparent solar control coating 14.

[0056] Example 1

[0057] The transparent organic substrate 12 is a polymethyl methacrylate acrylic-based substrate.

[0058] The liquid precursor of the transparent solar control coating is obtained by mixing CsxWOs nanoparticles until completely homogenized in a liquid matrix based on organosilane and a dye exhibiting an absorption peak between 450 and 550 nm, particularly around 490 nm. For example, the dye is a merocyanine compound marketed under the reference FDB-007 by Yamada Chemical.

[0059] The liquid precursor comprises approximately 3.15% by mass of CsxWOs nanoparticles and 0.05% by mass of dye.

[0060] The liquid precursor is deposited by centrifugal coating at 400 rpm.

[0061] The assembly formed by the transparent organic substrate 12 and the liquid precursor is then dried at a holding temperature of 80°C for 2 h.

[0062] The transparent solar control coating comprises slightly less than 10% by mass of CsxWOs and about 0.15% by mass of dye and has a thickness of 4.3 pm.

[0063] Example 2

[0064] The transparent organic substrate 12 is a polymethyl methacrylate acrylic-based substrate.

[0065] The liquid precursor of the transparent solar control coating is obtained by mixing CsxWOs nanoparticles until completely homogenized in a liquid matrix based on organosilane and a dye exhibiting an absorption peak between 450 and 550 nm, particularly around 490 nm. For example, the dye is a merocyanine compound marketed under the reference FDB-007 by Yamada Chemical.

[0066] The liquid precursor comprises approximately 3.70% by mass of CsxWOs nanoparticles and 0.05% by mass of dye.

[0067] The liquid precursor is deposited by centrifugal coating at 400 rpm.

[0068] The assembly formed by the transparent organic substrate 12 and the liquid precursor is then dried at a holding temperature of 80°C for 2 h.

[0069] The transparent solar control coating comprises slightly less than 11.7 wt% of CsxWOs and about 0.156 wt% of dye and has a thickness of 4.0 pm.

[0070] Example 3

[0071] The transparent organic substrate 12 is a polymethyl methacrylate acrylic-based substrate.

[0072] The liquid precursor of the transparent solar control coating is obtained by mixing CsxWOs nanoparticles in a liquid organosilane-based matrix with a mixture of two dyes, each dye exhibiting an absorption peak between 350 and 550 nm, until completely homogenized. For example, the first dye is a merocyanine compound marketed under the reference FDB-009 by Yamada Chemical, exhibiting an absorption peak around 395 nm, and the second dye is a merocyanine compound marketed under the reference FDB-002 by Yamada Chemical, exhibiting an absorption peak around 520 nm.

[0073] The liquid precursor comprises approximately 3.70% by mass of CsxWOs nanoparticles, 0.448% by mass of the first dye and 0.016% by mass of the second dye.

[0074] The liquid precursor is deposited by centrifugal coating at 400 rpm.

[0075] The assembly formed by the transparent organic substrate 12 and the liquid precursor is then dried at a holding temperature of 80°C for 2 h.

[0076] The transparent solar control coating comprises slightly less than 11.7% by mass of CsxWOs, 1.381% by mass of the first colorant and 0.05% by mass of the second colorant, and has a thickness of 4.0 pm.

[0077] Comparative example 1

[0078] Comparative example 1 differs from the example in that it does not include a dye.

[0079] The transparent solar control coating comprises slightly less than 10% by mass of CsxWOs and has a thickness of 3.4 pm.

[0080] The process steps are identical for the example and comparative example 1.

[0081] Comparative example 2

[0082] The liquid precursor consists of the matrix from the example above. The thickness of the coating obtained after drying is 4.0 pm.

[0083] The process steps are identical for the example and comparative example 2.

[0084] The characteristics of the transparent glazing in the example and comparative examples are presented in Table 1.

[0085] Scratch resistance is measured according to the Erichsen test defined according to ISO 1518:1992 for the 1 mm tip by applying increasing forces between 1 N and 10 N. For the 0.5 mm tip (Van Laar tip), a force between 1 N and 10 N is applied to the 0.5 mm tip.

[0086] [Table 1]

[0087] We observe that examples 1 to 3 exhibit a higher selectivity than comparative example 2.

[0088] Transparent glazing with a transparent solar control coating has the b* parameter allowing effective differentiation between a clear sky and a cloudy sky.

[0089] We also note the good scratch resistance of the transparent solar control coating.

[0090] Although the present description has been made with reference to a specific embodiment, it is evident that various modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. Furthermore, individual features of the various embodiments mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered illustrative rather than restrictive.

Claims

DEMANDS

1. Transparent aircraft glazing (10) comprising a transparent organic substrate (12) and a transparent solar control coating (14), the transparent glazing (10) having a selectivity greater than or equal to 1.17 and colorimetric transmission coordinates b* greater than or equal to -0.5 in the CIE L*a*b* space under a D65 illuminant and a 2° reference observer, preferably b* greater than or equal to 0, the transparent solar control coating (14) comprising nanoparticles dispersed in an organic, inorganic matrix or mixture thereof and the transparent solar control coating (14) comprising a dye.

2. Transparent glazing (10) according to claim 1, wherein the transparent solar control coating (14) is a transparent scratch-resistant coating.

3. Transparent glazing (10) according to claim 1 or 2, wherein the transparent solar control coating (14) has a thickness greater than or equal to 1 pm and less than or equal to 15 pm, preferably greater than or equal to 1 pm and less than or equal to 10 pm, even more preferably greater than or equal to 2 pm and less than or equal to 6 pm.

4. Transparent glazing (10) according to any one of claims 1 to 3, wherein the transparent solar control coating (14) has a nanoparticle content greater than or equal to 1% by mass and less than or equal to 35% by mass, preferably greater than or equal to 1% by mass and less than or equal to 25% by mass, even more preferably greater than or equal to 1% by mass and less than or equal to 20% by mass.

5. Transparent glazing (10) according to any one of claims 1 to 4, wherein the transparent solar control coating (14) has a colorant content greater than or equal to 0.005% by mass and less than or equal to 4.00% by mass, preferably greater than or equal to 0.010% and less than or equal to 2.0%.

6. Transparent glazing (10) according to any one of claims 1 to 5, wherein the nanoparticles are nanoparticles comprising CsxWOs and the dye has an absorption peak between 350 and 550 nm.

7. Transparent glazing (10) according to any one of claims 1 to 6, wherein the transparent organic substrate (12) comprises acrylic polymethyl methacrylate, polycarbonate.

8. Transparent glazing (10) according to any one of claims 1 to 7, wherein the transparent organic substrate (12) has a non-developable surface, the non-developable surface being coated with the transparent solar control coating.

9. Transparent glazing (10) according to any one of claims 1 to 8, wherein the transparent glazing (10) has a light transmission greater than or equal to 70%, preferably greater than or equal to 75%, even more preferably greater than or equal to 80%.

10. Transparent glazing (10) according to any one of claims 1 to 10, wherein the transparent glazing (10) has a selectivity greater than or equal to 1.20, preferably greater than or equal to 1.30, even more preferably greater than or equal to 1.

40.

11. Transparent glazing (10) according to any one of claims 1 to 11, wherein the transparent glazing (10) has a solar factor less than or equal to 70%.

12. Aircraft comprising transparent glazing according to any one of claims 1 to 11.

13. A method for manufacturing (100) a transparent glazing (10) according to any one of claims 1 to 11, comprising a liquid coating step (104) of the transparent organic substrate (12) with a liquid precursor of the transparent solar control coating.

14. A manufacturing process according to claim 13, comprising a drying step (106) of the liquid precursor of the transparent solar control coating to obtain the transparent solar control coating (14), the drying step (106) having a duration greater than or equal to 30 minutes and less than or equal to 4 hours, preferably greater than or equal to 1 hour and less than or equal to 3 hours, and the holding temperature being greater than or equal to 70°C and less than or equal to 130°C, preferably greater than or equal to 80°C and less than or equal to 120°C.

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