KR-102964495-B1 - POLYESTER RESIN COMPOSITION AND POLYESTER FILM FORMED THEREFROM

Abstract

The polyester resin composition according to the present invention can minimize the occurrence of streaks on the surface of a polyester film by controlling the elemental ratios of sodium (Na), antimony (Sb), phosphorus (P), and magnesium (Mg) relative to the total elemental weight, thereby minimizing the occurrence of deposits during the manufacturing process and lowering the melt resistivity.

Inventors

• 이승환
• 노형원
• 이규석

Assignees

• 도레이첨단소재 주식회사

Dates

Publication Date

20260512

Application Date

20230712

Claims (13)

1. A polyester resin formed by polymerizing 99 mol% ethylene glycol and 1 mol% neopentyl glycol as a diol component comprising 100 mol% terephthalic acid and ethylene glycol, a phosphate-based compound serving as a heat stabilizer, an antimony compound catalyst, and a metal compound, wherein the content of an element with respect to the total elemental weight of the polyester resin composition satisfies the following Formulas 1 to 3. Polyester resin composition having a Na content of 5 to 20 ppm, an Sb content of 50 to 130 ppm, a P content of 50 to 80 ppm, and an Mg content of 100 to 180 ppm: (Equation 1) 0.04 ≤ Na / Sb ≤ 0.4 (Equation 2) 0.28 ≤ P / Mg ≤ 0.8 (Equation 3) 1.88 ≤ (Mg+Sb) / P ≤ 6.2 The unit of weight for each element in the above Equations 1 to 3 is ppm.
2. delete
3. In paragraph 1, A polyester resin composition having a melt resistivity of 4.0 MΩ·cm or less.
4. delete
5. In paragraph 1, The above heat stabilizer is at least one selected from phosphoric acid and trimethylphosphate, in a polyester resin composition.
6. In paragraph 1, The above antimony compound catalyst is at least one selected from antimony tin oxide (ATO) and antimony triglyceride (ATG), in a polyester resin composition.
7. In paragraph 1, A polyester resin composition in which the metal compounds are magnesium acetate and sodium dihydrogen phosphate.
8. A polyester film formed from a polyester resin composition according to any one of claims 1, 3 and 5 to 7.
9. In paragraph 8, The above polyester film is a polyester film having a stripe height of 0.3㎛ or less on its surface.
10. In paragraph 8, A polyester film having a thickness of 19 to 250 μm.
11. In paragraph 8, The above polyester film is a biaxially stretched polyester film manufactured with a longitudinal and transverse stretching ratio of 3.0 to 7.0 times.
12. In paragraph 8, The above polyester film is a polyester film having one or fewer stripes observed via cross-Nicole per 1 m² area.
13. A polyester resin formed by polymerizing 99 mol% ethylene glycol and 1 mol% neopentyl glycol as a diol component containing 100 mol% terephthalic acid and ethylene glycol, comprising a phosphate-based compound as a heat stabilizer, an antimony compound catalyst, and a metal compound, having a melt resistivity of 4.0 MΩ·cm or less, and A polyester resin composition having a Na content of 5 to 20 ppm, an Sb content of 50 to 130 ppm, a P content of 50 to 80 ppm, and an Mg content of 100 to 180 ppm.

Description

Polyester resin composition and polyester film formed therefrom The present invention relates to a polyester resin composition and a polyester film formed therefrom, and more specifically, to a polyester resin composition capable of minimizing the occurrence of die-lines when a polymer is extruded from a Melting Line Pipe (MLP) to a T-die during the manufacture of a polyester film, and a polyester film formed therefrom. Generally, polyester films are utilized in a wide variety of products, such as display films, window films, polarizing films, carrier films, and packaging films, due to their excellent optical properties—such as transparency and lightfastness—as well as their cross-nicol polarization properties, and their superior moisture and chemical resistance. In particular, polyester films are applied to products requiring high optical and polarization characteristics, such as window films, display films, polarizing substrates, and polarizing release films; accordingly, there is a demand for films with superior optical and polarization properties to differentiate these products. In line with the need to improve the optical and polarization characteristics of such polyester films, there is also a growing demand for improvements regarding streaks that appear on the surface of polyester films. Since the streaks on the surface of such polyester films are clearly visible under cross-Nicol (polarization) conditions, research and development are underway for films capable of minimizing these streaks. Methods being studied to minimize streaks and improve the optical and polarization characteristics of such polyester films include improvements to the T-die environment (humidity, exhaust, air supply, etc.) where the polymer is extruded from the MLP (Melting Line Pipe), improvements to the T-die material, or improvements to the chip formulation ratio; however, there are currently limitations to minimizing streaks even through these methods. Figure 1 is a diagram illustrating the occurrence of streaks on the surface of a polyester film during the T-die process. FIG. 2 is a flowchart illustrating a method for manufacturing a polyester film according to one embodiment of the present invention. FIG. 3 is a drawing illustrating the discharge angle of a polyester resin composition according to one embodiment of the present invention. Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the invention in the drawings, parts unrelated to the description have been omitted, and the same reference numerals are assigned to identical or similar components throughout the specification. Additionally, thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Furthermore, where it is stated in this specification that one component is placed "on" or "above" another component, the component may be placed directly on the other component, or there may be components interposed between said components. Conversely, where it is stated that one component is placed "directly" or "on" another component, there may be no interposed components. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. In the event of a conflict, the present specification, including definitions, shall prevail. Additionally, methods and materials similar or equivalent to those described herein may be used in the practice or testing of the present invention, but suitable methods and materials are described herein. In this specification, "compound" is a broad concept that includes "monatomic molecules," "oligomers," and "polymer compounds including homopolymers and copolymers." In this specification, the term "includes" means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. First, Figure 1 is a diagram illustrating the occurrence of streaks on the surface of a polyester film during the T-die process, showing that streaks occur on the surface of a polyester film due to deposits generated during the T-die process. Generally, streaks that occur on the surface of a polyester film are defects that occur during the T-die process and are also referred to as die lines. Polyester films are typically manufactured using an electrostatic casting method; more specifically, an unoriented polyester film is manufactured by cooling and solidifying a polyester resin composition on a cooling drum (casting drum) using an electrosta