ONE-PIECE, TRANSPARENT ANTI-CONDENSATION SUBSTRATE

Abstract

A method includes applying a monolithic transparent substrate for separating a chamber cooled to a temperature of 0 to 4° C. from an ambient atmosphere, wherein a face of the monolithic transparent substrate in contact with the cooled air is provided with a low-emissivity layer, and another face of the monolithic transparent substrate in contact with the ambient atmosphere is provided with an anti-condensation layer

Claims

1. A method comprising applying a monolithic transparent substrate for separating a chamber cooled to a temperature of 0 to 4° C. from an ambient atmosphere, wherein a face of the monolithic transparent substrate in contact with the cooled air is provided with a low-emissivity layer, and another face of the monolithic transparent substrate in contact with the ambient atmosphere is provided with an anti-condensation layer.

2. The method as claimed in claim 1, wherein the anti-condensation layer comprises at least one of the polymer materials selected from the group consisting of polyurethane, polyacetal, polyester, poly(vinyl alcohol), poly(acrylic acid), polyethylene glycol, polypropylene glycol, polyol, polyvinylpyrrolidone, polyvinylpyridine, polyacrylate, polyacrylonitrile, polyacrylamide, polyacrolein, poly(vinyl acetate), silane or a copolymer of several of these, alone or as a mixture of several thereof.

3. The method as claimed in claim 1, wherein the anti-condensation layer is based on polyurethane.

4. The method as claimed in claim 1, wherein the anti-condensation layer comprises a polyurethane matrix with which polyvinylpyrrolidone molecules are interpenetrated.

5. The application as claimed in claim 1 wherein the anti-condensation layer has a thickness of between 5 and 80 μm.

6. The method as claimed in claim 1 wherein the anti-condensation layer forms the free main surface of an anti-fogging adhesive film.

7. The method as claimed in claim 1, wherein the substrate is made of mineral glass material or organic polymer.

8. The method as claimed in claim 5, wherein the anti-condensation layer has a thickness of between 10 and 70 μm.

9. The method as claimed in claim 8, wherein the anti-condensation layer has a thickness at most equal to 70 μm.

Description

EXAMPLE

[0020] Sheets of soda-lime float glass of 500 mm×1325 mm and 4 or 6 mm thick are coated with a low-emissivity layer on a first face, and with an anti-condensation layer on the second face,

[0021] Use is made, as low-emissivity layers, of the following stacks, classified by increasing emissivity (in %): [0022] 3%: glass/SnZnO 25 nm/ZnO 5 nm/Ag 10 nm/ZnO 5 nm/NiCr 1 nm/ZnO 5 nm/SnZnO 30 nm/TiOx 3 nm; [0023] 7%; glass/SnZnO 25 nm/ZnO 5 nm/Ag 6 nm/ZnO 5 nm/NiCr 1 nm/ZnO 5 nm/SnZnO 30 nm/TiOx 3 nm; [0024] 10%: glass/Si.sub.3N.sub.4 (5 nm)/SiO.sub.2 (40 nm)ITO (150 nm)/SI.sub.3N.sub.4 (12 nm)/SiO.sub.2 (75 nm)/TiO.sub.2 (4 nm) and [0025] 15%: glass/SnO.sub.2 (30 nm)/SiO.sub.2 (30 nm)/SnO.sub.2:F (370 nm).

[0026] In tests numbered 1 to 6, use is made, as anti-condensation layers, of the anti-frost and anti-fogging layers sold by Saint-Gobain Glass under the registered trademark Everclear®, having a thickness as indicated below. These layers consist of a polyurethane matrix with which polyvinylpyrrolidone molecular chains are interpenetrated.

[0027] In tests 7 to 14, use is made, as anti-condensation layers, of hydrophilic layers obtained by grafting silanes with a poly(ethylene oxide) (PEO) chain to the glass substrate. The silanes used for the anti-fogging coatings comprise a hydrophilic poly(ethylene oxide) (PEO) chain and three OH groups bonded to the Si atom; the OH groups of the silane react (condensation) with the OH groups of the glass forming silanol (Si—O—Si) bonds. The silanes may also be fluorinated in order to impart self-cleaning properties. Two silanes were used: [0028] a) in tests nos. 7 to 10, the silane sold by Gelest under the reference Silane SiH6188 and of formula:

##STR00001## [0029] and [0030] b) in tests nos, 11 to 14, the fluorosilane sold by Specific Polymers under the reference SP-SG 192-193 and of formula:

##STR00002##

[0031] The glass sheets are positioned so as to delimit a refrigerated chamber at a setpoint temperature of 0° C. The ambient atmosphere is at 25° C. and 60% relative humidity. The low-emissivity layer is on the refrigerated chamber side and the anti-condensation layer is on the “ambient atmosphere” side.

[0032] The conditions of the fourteen tests are recorded in the table below.

TABLE-US-00001 Test Glass thickness Layer emissivity Anti-condensation no. (mm) (%) layer thickness 1 4 3 20 μm 2 4 7 20 μm 3 6 10 40 μm 4 6 15 40 μm 5 6 10 50 μm 6 6 15 50 μm 7 4 3 Several nm 8 4 7 Several nm 9 6 10 Several nm 10 6 15 Several nm 11 4 3 Several nm 12 4 7 Several nm 13 6 10 Several nm 14 6 15 Several nm

[0033] No formation of fogging on the glass sheet is observed in any of the fourteen tests.