Biaxially oriented polyester film

Abstract

The invention relates to colored biaxially oriented polyethylene terephthalate film, in particular biaxially oriented polyethylene terephthalate and polypropylene film.

Description

[0001] DESCRIPTION

[0002] BIAXIALLY ORIENTED POLYESTER FILM

[0003] Technical Field of the Invention

[0004] The invention relates to colored biaxially oriented polyester film, in particular biaxially oriented polyethylene terephthalate (BOPET) film.

[0005] State of the art regarding the invention

[0006] Biaxially oriented polyethylene terephthalate (BOPET) films are widely used in industry due to their superior oxygen barrier properties, chemical resistance, better mechanical properties and stiffness compared to other polyolefin (polypropylene and polyethylene) films.

[0007] In the market, rotogravure coating is generally used for coloring films. Rotogravure is not only costly, but also requires extra processes, resulting in loss of time and labor as well as cost loss.

[0008] In addition to rotogravure, the less costly extrusion method is also used for coloring. The disadvantage of the extrusion method is that purge process is required at the entrance and exit of the color film. Especially in BOPET production lines, crystallization and drying are required for the base coat and these processes can take about 4 hours or more in total. In the state of the art, color agents such as titanium dioxide or barium sulfate are used in the base layer of the film to produce white film. For different colors other than this, coloring is provided by secondary processes as mentioned above.

[0009] WAL labels containing BOPET film are described in document numbered TR2015 / 03980. In the production of the aforementioned bidirectionally stretched polyester film, a polyester homopolymer containing silica additive or a coloring additive containing silica additive (masterbatch) is used together with an undoped polyester homopolymer (virgin resin).

[0010] A biaxially oriented polyester film is disclosed in document with publication number US20080318073A1. The main layer of said film, which is positioned in the center, contains yellow and red paint, and the layers around the main layer contain yellow and red paint at a rate of less than 0,1%. Another problem encountered in the use of the coloring additive in the main layer in the center is the inability to ensure color homogeneity at the entrance and exit of the production. In this way, high waste rates are reached in production, which is reflected in the cost and price of the product.

[0011] As a result, all abovementioned problems have made it necessary to make an improvement in the relevant technical field.

[0012] Objects of the Invention

[0013] The main object of the present invention is to provide a BOPET film structure in which color homogeneity is achieved.

[0014] Another object of the present invention is to prevent static electricity.

[0015] The object of the present invention is to provide a biaxially oriented polyester film structure which is colored at a lower thickness.

[0016] The object of the present invention is to achieve high brightness and low haze.

[0017] The object of the present invention is cost reduction.

[0018] A further object of the present invention is to provide a heat absorbing colored biaxially oriented polyester film structure.

[0019] A further object of the present invention is to provide a heat reflective colored biaxially oriented polyester film structure.

[0020] Brief Description of the Invention

[0021] The present invention relates to a biaxially oriented polyethylene terephthalate film comprising a peripheral layer provided around a central main layer having at least three layers, wherein said three layers comprise a coloring additive provided only around the main layer. Providing coloring in the peripheral layers eliminates color homogeneity problems and also increases scratch resistance. Definitions of the Figures Describing the Invention

[0022] The figures and related explanations used so as to better explain the film developed with the present invention are given below.

[0023] Figure 1. Schematic representation of the layers of a configuration of the film of the present invention

[0024] Definitions of Elements / Sections / Parts that Constitute the Invention

[0025] The parts and parts in the figures are enumerated and the corresponding of each number is given below in order to better explain the film developed with this invention:

[0026] 1. Film

[0027] 10. Main layer

[0028] 11. Front surface

[0029] 12. Rear surface

[0030] 20. Peripheral layer

[0031] 30. Outer surface layer

[0032] Detailed Description of the Invention

[0033] The subject of the invention relates to colored biaxially oriented polyester film, in particular biaxially oriented polyethylene terephthalate film (1).

[0034] The polyester film (1) of the present application comprises at least three layers and is in particular made of biaxially oriented polyethylene terephthalate (BOPET). These layers are stacked on top of each other so as to form the film (1) structure. One of these layers is called the main layer (10) and the other two are called the peripheral layers (20).

[0035] With reference to Figure 1, said peripheral layers (20) are positioned to contact the front surface (11) and the rear surface (12) of said main layer (10). These three layers are fixed to each other.

[0036] While said main layer (10) does not contain any coloring additives (masterbatch), one or both of the peripheral layers (20) contain coloring additives and the overall coloring of the film (1) is carried out through these peripheral layers (20). Preferably said colored additive contains silica. The silica additive prevents blocking and also ensures that the film (1) can be opened and used without any problems. In addition, the silica additive prevents the surfaces of the film (1) from completely touching each other and creates micro-gaps between the layers of the film.

[0037] Said coloring additive is preferably provided in gold and amber. It was observed that the heat absorption of the gold-colored film (1) was particularly high.

[0038] The film (1) made of BOPET can be produced with a thickness down to 12 microns. Preferably, the film (1) is between 12-75 microns, in particular between 12-18, microns.

[0039] In one embodiment of the invention, a metallic layer (not shown in the figures) may be present on one of the outermost surfaces of the film (1). Said metallic layer increases the heat reflecting abilities of the film (1).

[0040] In one embodiment of the invention, there is a secondary process as a metallized coating. Metallizing is a coating process performed with aluminum vapour of the film under vacuum. BOPET film in brown-orange tones, which is produced using color masterbatch on the BOPET production line, turns golden after metallized coating.

[0041] The most intensive use of the film (1) structure mentioned above is in packaging, especially flexible packaging. In addition, the film (1) is used in textiles in general, especially in tents and clothing.

Claims

CLAIMS1. A biaxially oriented polyethylene terephthalate (BOPET) film (1), characterized in that, it comprises the following; a base layer (10) without coloring additives and peripheral layers (20) positioned so as to dispose said main layer (10) between them, at least one of which contains a coloring additive.

2. A film (1) according to claim 1, characterized in that; both peripheral layers (20) contain coloring additives.

3. A film (1) according to claim 1 or 2, characterized in that; the coloring additive has a golden or amber color.

4. A film (1) according to claim 1, characterized in that; the peripheral layers (20) are positioned such that one is in contact with the front surface (11) of the main layer and the other is in contact with the rear surface (12) of the main layer.

5. A film (1) according to claim 1, characterized in that; it has 12-75 micron thickness.

6. A film (1) according to claim 1, characterized in that; it has 12-18 micron thickness.

7. A film (1) according to any of the preceding claims, characterized in that; said coloring additive comprises silica.

8. A film (1) according to any of the preceding claims, characterized in that; it comprises a metallized layer.

9. Packaging made of a biaxially oriented polyethylene terephthalate film (1) according to any one of the preceding claims.

10. A textile article made of a biaxially oriented polyethylene terephthalate film (1) according to any one of claim 1-8.

11. A garment made of a biaxially oriented polyethylene terephthalate film (1) according to any one of claim 1-8.

12. A tent made of a biaxially oriented polyethylene terephthalate film (1) according to any one of claim 1-8.

Images