CN-122003468-A - Polyester film, process for producing the same, and resin composition

Abstract

The invention provides a polyester film with good electrostatic adhesion, a manufacturing method thereof and a resin composition used for the manufacturing method. The polyester film contains 0.01 to 950 mass ppm of an ionic compound having dissociation energy Q (kJ/mol) between anions and cations of 850 or less.

Inventors

• Watayo Naoko
• HIGO ERI
• Tong Kouliang
• Tangai Yasuhiko
• HAYAKAWA SHOTA
• MURATA HIROYUKI
• ITO TAKUYA

Assignees

• 东洋纺株式会社

Dates

Publication Date

20260508

Application Date

20241011

Priority Date

20231013

Claims (15)

1. 1. A polyester film comprising 0.01 to 950 mass ppm of an ionic compound having an dissociation energy Q (kJ/mol) between anions and cations of 850 or less.
2. 2. The polyester film according to claim 1, wherein the melting resistivity of the resin constituting the polyester film is 20X 10 8 . Omega. Cm or less.
3. 3. The polyester film according to claim 1, wherein the melting resistivity of the resin constituting the polyester film is 0.001X 10 8 . Omega. Cm or more.
4. 4. The polyester film according to claim 1, wherein at least 1 ion of anions and cations constituting the ionic compound has an ionic radius of 10 a or less.
5. 5. The polyester film according to claim 1, wherein an absolute value of an average charge density of at least 1 ion of anions and cations constituting the ionic compound is 0.0025 e/a 2 or more and 0.075 e/a 2 or less.
6. 6. The polyester film according to claim 4, wherein the cation constituting the ionic compound has an ionic radius of 2a or more.
7. 7. The polyester film according to claim 5, wherein the average charge density of the cations constituting the ionic compound has an absolute value of 0.015 e/a 2 or less.
8. 8. The polyester film according to claim 1, which contains less than 100 mass ppm of the ionic compound.
9. 9. The polyester film according to claim 1, wherein the resin constituting the polyester film is polyethylene terephthalate and/or polyethylene naphthalate.
10. 10. A method for producing a polyester film containing an ionic compound having dissociation energy Q (kJ/mol) of anions and cations of 850 or less, the method comprising: A step of mixing a polyester resin composition A comprising a polyester resin A and an ionic compound having dissociation energy Q (kJ/mol) of anions and cations of 850 or less and a polyester resin B having a melting resistivity greater than that of the polyester resin composition A, and And forming a mixture containing the polyester resin composition A and the polyester resin B into a film.
11. 11. The process according to claim 10, wherein the polyester resin composition A has a melting resistivity of 5X 10 8 . Omega. Cm or less.
12. 12. A method for producing a polyester film containing an ionic compound having dissociation energy Q (kJ/mol) of anions and cations of 850 or less, the method comprising: A step of mixing a polyester resin composition A comprising a polyester resin A and an ionic compound having dissociation energy Q (kJ/mol) of anions and cations of 850 or less and a polyester resin B having a melting resistivity of 1X 10 8 Ω & cm or more, and And forming a mixture containing the polyester resin composition A and the polyester resin B into a film.
13. 13. The method for producing a polyester film according to claim 1, which comprises: A step of mixing a polyester resin composition A comprising a polyester resin A and an ionic compound having dissociation energy Q (kJ/mol) of anions and cations of 850 or less and a polyester resin B having a melting resistivity greater than that of the polyester resin composition A, and And forming a mixture containing the polyester resin composition A and the polyester resin B into a film.
14. 14. The method for producing a polyester film according to claim 1, which comprises: A step of mixing a polyester resin composition A comprising a polyester resin A and an ionic compound having dissociation energy Q (kJ/mol) of anions and cations of 850 or less and a polyester resin B having a melting resistivity of 1X 10 8 Ω & cm or more, and And forming a mixture containing the polyester resin composition A and the polyester resin B into a film.
15. 15. A polyester resin composition comprising a polyester resin and an ionic compound, wherein the dissociation energy Q (kJ/mol) between anions and cations of the ionic compound is 850 or less, and the polyester resin composition has a melting resistivity of 0.0001X 10 8 Ω & cm or more and 0.1X 10 8 Ω & cm or less.

Description

Polyester film, process for producing the same, and resin composition Technical Field The present application claims priority based on Japanese patent application No. 2023-177741, japanese patent application No. 2024-031431, japanese patent application No. 2024-031434, japanese patent application No. 2024-055982, japanese patent application No. 2024-055985, japanese patent application No. 2024-055986, japanese patent application No. 2024-076078, japanese patent application No. 2024-094269, japanese patent application No. 2024-094270, japanese patent application No. 2024-113434, japanese patent application No. 2024-113436 and Japanese patent application No. 2024-113437. The contents of these patent applications are incorporated by reference into the present specification in their entirety. The present invention relates to a polyester film, a method for producing the same, and a resin composition used for the method. Background Polyester films represented by polyethylene terephthalate have been used for various purposes since they have excellent mechanical properties, heat resistance, electrical insulation, chemical resistance, and the like. In general, a polyester film is produced by bringing a sheet melt-extruded by an extruder into close contact with the surface of a rotating cooling drum or the like, and is used as an unstretched film or a stretched film obtained by further uniaxially or biaxially stretching an unstretched film. In order to improve the uniformity of the thickness of these unstretched films and stretched films, and to increase the production speed, it is necessary to rapidly and uniformly adhere the melt-extruded sheet to the surface of a cooling drum or the like. As a method of adhesion, an electrostatic adhesion method is widely known. In this method, an electrode is provided between a pressing nozzle and a cooling rotating drum, and a high voltage is applied to deposit static electricity on the surface of a molten sheet, so that the molten sheet is attached to the surface of the cooling rotating drum by means of electrostatic force. In the electrostatic bonding method, it is known that it is effective to increase the charge amount on the surface of the molten sheet, and to increase the charge amount, it is effective to reduce the resistivity of the polyester as a raw material. As a method for reducing the specific resistance, addition of an alkali metal (group i) or alkaline earth metal (group ii) compound or the like is performed. However, in these methods, the added metal is likely to precipitate as a foreign matter, and may cause defects in the film or decrease in transparency, and a method of reducing the precipitated foreign matter by optimizing the addition amount, the addition timing, and the like has been proposed (for example, patent document 1). Prior art literature Patent literature Patent document 1 Japanese patent laid-open No. 2002-327053 Disclosure of Invention Problems to be solved by the invention In particular, in recent years, polyester films have been used as an essential film in fields requiring high precision, such as optical films, engineering films, and high barrier films. It is desired to realize a polyester film having high productivity, particularly a polyester film having good electrostatic adhesion and high clarity, which is less problematic due to precipitation of additives, by an electrostatic adhesion method. In view of the above, an object of the present invention is to provide a polyester film having excellent electrostatic adhesion, particularly a polyester film having high clarity and being usable for various applications. In recent years, from the viewpoint of the sustainable development objective (Sustainable Development Goals: SDGs), polyester films have also been widely used, such as polyester using a biomass-derived raw material, recycled polyester obtained by recycling a used polyester product such as a bottle, and chemically recycled polyester obtained by polymerizing a monomer and/or oligomer obtained by decomposing the used polyester as a raw material, and among polyester films using these as a raw material, polyester films having the same specific resistance and high clarity have been desired. The resin used in the polyester film is often added with an electrostatic adhesion agent and lubricant particles, but from the viewpoints of economy and environmental load reduction, a method of mass-producing a polyester containing no additives and the like and adding additives for the film is also adopted. In view of the above, an object of the present invention is to provide a polyester film having excellent electrostatic adhesion, particularly a polyester film having high clarity and being usable for various applications, a method for producing the same, and a resin composition used in the method. Solution for solving the problem As a result of intensive studies, the present inventors have found that the above problems can be solved by blending an