Unilaterally mat, sealable, UV-stabilized, flame resistant, co-extruded, biaxially oriented polyester film, method for the production and the use thereof

DETAILED DESCRIPTION OF THE INVENTION A transparent, UV-resistant, sealable, and biaxially oriented polyester film with one matt side is therefore provided and in particular has very good sealability, is cost-effective to produce, has improved processability, and has improved optical properties.
The invention permits the sealing range of the film to be extended to low temperatures, the seal seam strength of the film to be increased, and at the same time better handling of the film to be provided than in the prior art.
It has also been ensured that the film is capable of processing even on high-speed machinery.
Regrind arising directly during production of the film can be reintroduced to the extrusion process at a concentration of up to 60% by weight, based on the total weight of the film, without any significant resultant adverse effect on the physical properties of the film.
Since the film of the invention is particularly intended for outdoor applications and/or critical indoor applications, it is to have high UV resistance.
High UV resistance means that sunlight or other UV radiation causes no, or only extremely little, damage to the films.
In particular, when used outdoors for a number of years films should show no yellowing, embrittlement, or surface-cracking, and should have unimpaired mechanical properties.
High UV resistance means that the film absorbs UV light and does not begin to transmit light until the visible region has been reached.
The UV stabilizer(s) is/are advantageously fed directly in the form of masterbatch(es) during film production, the concentration of the UV stabilizer(s) preferably being in the range from 0.
01 to 5.
0% by weight, with preference from 0.
1 to 3.
0% by weight, based on the weight of the respective layer of the polyester used.
The film of the invention generally has at least three layers, the layers encompassed then being the base layer B, the sealable outer layer A, and the matt outer layer C.
At least 90% by weight of the base layer B of the film is generally composed of a thermoplastic polyester