FR3118902A1 - SAFETY FILM FOR GLASS ELEMENTS - Google Patents

Abstract

The invention is a security film for manual application on glazing, the film comprising, in order: at least one adhesive layer, of the pressure-sensitive type (PSA); at least one layer of a soft, moisture-insensitive thermoplastic, in particular thermoplastic polyurethane; at least one layer of polyethylene terephthalate (PET). The film has the advantage of being easy to apply manually and of providing the glazed element with improved impact resistance properties.

Description

SAFETY FILM FOR GLASS ELEMENTS

The invention relates to the field of security films providing glazing, or any other glazed elements, with improved impact resistance properties. These safety films also prevent the dispersion of glass shards.

Document FR 2 311 762 describes security films comprising several laminated layers of polyethylene terephthalate (PET) and a pressure-sensitive adhesive layer on one side of one of the PET layers .

Document FR 2 579 609 describes a self-adhesive sheet of plastic material for application to the exterior face of glazing and having anti-laceration and self-healing properties. The film has at least one layer of polyurethane (PU).

In Example 3, a layer of self-healing PU is deposited on one side of a PET film and on the other side of the PET a layer of adhesive, such as a pressure-sensitive adhesive (PSA) .

To improve impact resistance, films comprising several layers of plastic material have been proposed.

Document WO 2001/96115 describes a protective film composed of three layers 0.05 mm thick.

These films then lose their flexibility and their manual application on a glazed element is painful. It is not possible to cut the film directly on the glazed element. It is necessary to pre-cut the film to the exact size of the glazing before applying it.

Document US 2009/0246438 describes window protection films, in particular in the event of a hurricane. Movies can be installed manually. The thickness of the films is between 8 (203 µm) and 20 mil (508 µm).

The films described have a layer of PVB sandwiched between two layers of PET. As PVB layers are sensitive to humidity, this type of film applied to an external face of glazing risks degrading rapidly.

The inventors have developed a safety film for glazed elements, which is easy to apply manually and which provides the glazed element with improved impact resistance properties.

The subject of the present invention is a safety film for manual application on glazing, the film comprising, in order:

• at least one adhesive layer, of the pressure-sensitive type (PSA);
• at least one layer of a soft, moisture-insensitive thermoplastic;
• at least one layer of PET.

The ratio between the thickness of the thermoplastic layer and the thickness of the PET layer is advantageously between 0.2 and 5.0, preferably between 0.4 and 3.0 and even more preferably 0.8 and 2.0.

In particular, the thermoplastic layer is chosen from thermoplastic polyurethanes (TPU), ethylene-vinyl acetate (EVA), polypropylene (PP), ...

In particular, the total thickness of the film is between 100 and 600 μm, preferably between 150 and 500 μm,

Advantageously, the film has a flexibility of between 0.8 and 14 mN.m, preferably between 1 and 7 mN.m.

The security film may also comprise an outer protective layer (also called “hardcoat”), deposited on the PET layer.

The security film according to the invention may also include an additional PET layer between the adhesive layer and the PET layer.

Advantageously, the adhesive layer comprises an anti-UV agent.

The present invention also relates to the use of a security film as described above, for manual application on a glazed element.

In particular, the glazed element is a glazing and the film is applied to the side of the glazing arranged inside the building.

The use according to the invention makes it possible to improve the impact resistance properties of the glazed element.

The following examples illustrate the invention in a non-limiting manner.

Examples

Different films composed of a layer of thermoplastic polyurethane (TPU) and a layer of polyethylene terephthalate (PET) of different thicknesses have been produced. A layer of a pressure-sensitive type adhesive (known in English as PSA) is applied to the TPU layer. A protective film is applied to the adhesive layer. This protective film is intended to be removed by the user just before applying the film to the glazing.

TPU Thickness
PET thickness Total thickness Flexural modulus Standard deviation Impact resistance Standard deviation (mil) (µm) (mil) (µm) (mil) (µm) (mN.m) m Ex 1 6 152 4 102 10 254 1.33 0.19 2.16 0.34 Ex 2 6 152 7 178 13 330 2.76 0.17 2.85 0.66 Ex 3 9 228 7 178 16 406 4.94 0.97 4.28 0.17 Ex 4 1 26 6 152 7 178 Ex 5 4 102 3 76 7 178 ex comp 1 14 ... 13.4 0.42 3.15 0.27 ex comp 2 7 ... 2.89 0.41 1.35 0.27

To measure the mechanical performance of impact resistance, a ball drop test is carried out on single sheets of 6 mm thick glass with the film glued on the underside. A drying time of 6 weeks is respected.

The experimental setup is the same as that of standard EN356. To establish a Mean Break Height (MBH), a sequence of impact heights is performed: if the sample fails, the drop height is decreased; and if the sample resists, the drop height is increased. The mean value of the break height is the height at which 50% of the samples pass and 50% fail the test. This MBH value is used to compare the impact resistance performance of different films.

To assess the flexibility of the films, a standard stiffness meter is used. The film, a 4cm wide strip, is fixed on one edge in the clamping jaw. The device exerts a bending force at a distance of 25mm from the jaw and bends the film up to a 90° angle. The rigidity of the film is expressed in the form of a flexural modulus "bending stiffness" in mN.m.

Claims (11)

Safety film for manual application on a glazed element, the film comprising, in order:

• at least one adhesive layer, of the pressure-sensitive type (PSA);
• at least one layer of a soft, moisture-insensitive thermoplastic;
• at least one layer of polyethylene terephthalate (PET).

Security film according to the preceding claim, characterized in that the ratio between the thickness of the thermoplastic layer and the thickness of the PET layer is between 0.2 and 5.0, preferably between 0.4 and 3 .0 and more preferably 0.8 and 2.0. Security film according to any one of the preceding claims, characterized in that the thermoplastic layer is chosen from among thermoplastic polyurethanes (TPU), ethylene-vinyl acetate (EVA), polypropylene (PP). Security film according to any one of the preceding claims, characterized in that its total thickness is between 100 and 600 µm, preferably between 150 and 500 µm. Security film according to any one of the preceding claims, characterized in that it has a flexibility of between 0.8 and 14 mN.m, preferably between 1 and 7 mN.m. Security film according to any one of the preceding claims, characterized in that it also comprises an outer protective layer, deposited on the PET layer. Security film according to any one of the preceding claims, characterized in that it further comprises an additional PET layer between the adhesive layer and the PET layer. Security film according to any one of the preceding claims, characterized in that the adhesive layer comprises an anti-UV agent. Use of a security film according to any one of the preceding claims, for manual application on a glazed element. Use according to the preceding claim, characterized in that the glazed element is a glazing; the film being applied to the side of the glazing arranged inside the building. Use according to any one of Claims 9 to 10, for improving the impact resistance properties of the glazed element.