WO2012077093A2

WO2012077093A2 - Windows with anti-freezing layer

Info

Publication number: WO2012077093A2
Application number: PCT/IB2012/050378
Authority: WO
Inventors: Wilhelmus Van Den Elshout
Original assignee: Hd Inspiration Holding B.V.
Priority date: 2010-12-07
Filing date: 2012-01-26
Publication date: 2012-06-14
Also published as: WO2012077093A8; WO2012077093A3; NL2005829C2

Abstract

The invention relates to vehicle windows provided with a plastic film of a polyfluorinated polyolefin in order to prevent freezing of ice with high adhesion to the glass surface. The invention furthermore relates to the use of a polyfluorinated polyolefin film on vehicle windows to prevent freezing of ice with high adhesion to the glass surface. Preferably, the polyfluorinated polyolefin is a PFA or FEP film. Any of the windows can be provided with a film, both on the outside and/or the inside.

Description

WINDOWS WITH ANTI-FREEZING LAYER.

Freezing surfaces, especially windscreens or more in particular vehicle windows and exterior mirrors, do hamper clear vision and should be cleared before participating in traffic.

In order to clean the window, generally one uses an ice scraper or one applies defrosting sprays. Some cars have electrically heated windows. These methods are inconvenient and take time. A window with an anti-freezing layer based on glass, having on one side indium and tin oxide is described in WO2009/149889 A1 . Windows having such layer are anti freezing to a temperature of -18C. However, clouds, wind and high humidity will still make the window freeze. Furthermore, this technique requires high technology glass manufacturing.

The invention relates to a vehicle window with anti-freezing layer that can be provided more easily.

According to the invention, the vehicle window is provided with a plastic film of a

polyfluorinated polyolefin. The invention furthermore relates to the use of a polyfluorinated polyolefin film on vehicle windows to prevent freezing with high adhesion to the glass surface. In this way, the present invention provides a surface treatment whereby water or ice can not adhere anymore to the screen by making the surface extremely hydrophobic. As far as some residual adhesion is present, the layer of ice and/or frozen snow can be easily wiped away with a blade (without the need for scraping). A further advantage is that rain is blown away from the window when a car drives at a speed of about 20-30 km/hr or more. Hence, it is not necessary to use wipers and vision is improved.

In a preferred embodiment, a film of fluorinated polymer is applied on top of the outside of the window screen. In another embodiment, the film is applied to the inside of the window, as that allows more easy cleaning on the inside of the car, and it prevents ice adhering, which may take place when the car is still cold.

The film has high transparency, in order to assure that the transparency of the screen is not or barely affected. The transparency preferably is about 95% or more for the visible wave length region of 400-800 nm. Preferably, the transparency is about 97% or higher, like for example 98% or higher. The most appropriate fluorinated materials are Dupont's Teflon FEP and Teflon PFA films.

Teflon® FEP is a fluorinated ethylene propylene resin that meets the ASTM Standard Specification for FEP— Fluorocarbon Molding and Extrusion Materials under ASTM

Designation D21 16-95a. It is available as pellets or as stabilized aqueous dispersions.

Applications for this family of resins include coating, melt extrusion, and impregnating.

Products made from Teflon® FEP are known for their excellent chemical resistance, superior electrical properties, and high service temperatures of up to 200 °C (392°F). In addition, Teflon® FEP provides outstanding low-temperature toughness and unique flame resistance.

Teflon® PFA is a perfluoroalkoxy copolymer resin available in pellet or powder. Teflon® PFA combines the processing ease of conventional thermoplastic resins with the excellent properties of Teflon® polytetrafluoroethylene (PTFE). Products manufactured from Teflon® PFA can offer continuous service temperatures up to 260 ^ (500 °F). What's more, Teflon® PFA provides superior creep resistance at high temperatures, excellent low-temperature toughness, and exceptional flame resistance.

Teflon® PFA or FEP fluoropolymer resins are processed by conventional melt-extrusion techniques and by injection, compression, rotational, transfer, and blow-molding processes. The high melt strength and heat stability of these resins permit the use of relatively large die openings and high-temperature draw-down techniques, which increase processing rates. Reciprocating screw injection molding machines are recommended. Corrosion-resistant metals should be used in contact with the molten resin. Long extruder barrels, relative to diameter, are used to provide residence time for heating the resin to 316° to 427 ^<C (600° to 800 °F).

More specific one can apply a Teflon® FEP or PFA foils, which have a self adhesive site. These foils can be easily applied on a window and have a transparency of >98%. The surface thus obtained is highly water repellent. As a result the surface will not freeze. Ice which "sits on top" of the screen is easily wiped of.

Teflon ® FEP or PFA films are commercially available, for example from Dupont. Films of FEP are preferred, because they are cheaper.

The film can be applied on any of the windows of a car. Additionally, or alternatively, the film can also be applied on one or more exterior car mirrors. In one embodiment, the film is applied on the side windows, because these windows generally are flat, and a film is easily applied. For similar reasons, the film may be applied on exterior car mirrors as well.

In another embodiment, the film is applied to the rear window, as this window often gathers dirt. The dirt is now more easily removed because of the low adherence.

In yet another embodiment, the foil is applied to the front window, as that window is known to gather most ice and/or snow.

In one embodiment, it is preferred to cover the whole of the glass window with the plastic film. However, in particular for the front and back window, this is not necessary. Hence, it can be preferable, to adhere the film to e.g. between 95 and 60% of the window surface. The film would be placed in the middle of the window, leaving a strip of uncovered glass at the edges of the window. The advantage if this way of adhering the film is, that no film is applied onto the parts of the window which are more difficult to access. Also, at the edges, the glass may be more curved, which makes it more difficult to apply a film. In another embodiment of the invention, the film is applied on the inside of the window. In particular in cold climates, also the inside can become iced, and a window provided with a film on the inside allows easy wiping away of any material adhered to the window. Also in this case, the film can be applied to the front window, the rear window and/or any of the side windows.

Example

On the back window of a car, a square piece of PEF foil was applied. After a night of freezing with high relative humidity, the window comprised a layer of frost. The wiper of the rear window was used to wipe the rear window. All the ice remained adhered to the window, but on the place were the foil was attached. A photograph of a rear window after the one wipe is shown in Figure 1 . The square which is clean after one wipe can be easily observed, and is the place where the film was applied.

The invention has been described by reference to certain embodiments discussed above. It will be recognized that these embodiments are susceptible to various modifications and alternative forms well known to those of skill in the art without departing from the spirit and scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention, which is defined in the accompanying claims.

Claims

I . Vehicle window provided with a polyfluonnated polyolefin layer.

2. Use of a polyfluonnated polyolefin layer to prevent freezing of ice with high adhesion to a surface of a vehicle window.

3. Vehicle window or use according to any one of the previous claims, wherein the

polyfluonnated polyolefin layer comprises PFA or FEP.

4. Vehicle window or use according to any one of the previous claims, wherein the window is a rear window.

5. Vehicle window or use according to any one of the previous claims, wherein the window is a side window.

6. Vehicle window or use according to any one of the previous claims, wherein the window is a front window.

7. Vehicle window or use according to any one of the previous claims, wherein the

polyfluonnated polyolefin layer is disposed on an outer surface of the window.

8. Vehicle window or use according to any one of the previous claims, wherein the

polyfluonnated polyolefin layer is disposed on an inner surface of the window.

9. Vehicle window or use according to claim 7, wherein the polyfluonnated polyolefin layer is disposed on from 100 to 60% of the outer surface of the window, preferably between 95 and 60%. 10. Vehicle window or use according to claim 8, wherein the polyfluonnated polyolefin layer is disposed on from 100 to 60% of the inner surface of the window, preferably between 95 and 60%.

I I . Vehicle window or use according to any of the preceding claims, wherein the

polyfluonnated polyolefin layer is disposed on both an inner and an outer surface of the vehicle window.

12. Vehicle window or use according to any of the preceding claims, wherein the

polyfluonnated polyolefin layer is a film comprising polyfluonnated polyolefin.

13. Vehicle window provided with a plastic film of a polyfluorinated polyolefin.

14. A vehicle provided with at least one vehicle window according to any of claims 1 to 13.

15. A vehicle mirror, preferably an external vehicle mirror, provided with a polyolefin

polyfluorinated layer.