KR100810400B1 - Method for preparing conductive oxide thin film using PETG plastic substrate - Google Patents

Abstract

The present invention relates to a method for producing a conductive oxide thin film using a PETG plastic substrate, and more particularly, polyethylene terephthalate glycol (PETG) containing 30 mol% or less of cyclohexanedimethanol (CHDM) based on the total glycol component. RF plasma sputtering deposition on a substrate made of a sheet having a thickness of 100 to 400 μm using a process pressure of 1 to 20 mTorr and a substrate temperature of 25 to 150 ° C., or a roll-to-roll at a roller speed of 0.1 to 100 m / min. The present invention relates to a method of manufacturing a conductive oxide thin film by depositing an indium tin oxide (ITO) thin film by electron beam deposition using a roll. According to the present invention, in a polyester polymerized with terephthalic acid (TPA) and ethylene glycol (EG), an amorphous PETG plastic substrate having improved transparency, processability and physical properties is provided by preventing crystallization by replacing a certain amount of EG with CHDM. It is applicable as a substrate agent for transparent electrodes of display elements, such as a touch panel and plastic LCD.

PETG, Plastic, Substrate, Conductive, Oxide Thin Film, Polyester, Cyclohexanedimethanol

Description

Method for preparing conductive oxide thin film using PETG plastic substrate

1 is a view schematically showing a surface treatment and RF magnetron deposition apparatus using a PETG substrate according to the present invention.

2 is a schematic view of an ion surface treatment and electron beam deposition apparatus according to a roll-to-roll (web to coating) process using a PETG substrate according to the present invention.

※ Explanation of code about main part of drawing ※

10 and 20: vacuum chamber 11: substrate support 12: gas inlet

21: substrate roller 22: cooling drum

The present invention relates to a method for producing a conductive oxide thin film using a PETG plastic substrate, and more particularly, polyethylene terephthalate glycol (PETG) containing 30 mol% or less of cyclohexanedimethanol (CHDM) based on the total glycol component. The present invention relates to a method of manufacturing a conductive oxide thin film having excellent transmittance and low surface resistance by depositing an indium tin oxide (ITO) thin film on a used plastic substrate.

Background Art [0002] Sheets made of optical quality glass or quartz have conventionally been used as substrate materials for transparent electrode materials of display elements such as touch panels and display devices such as plastic liquid crystal displays (LCDs). The substrate may be transparent, translucent or opaque, but typically transparent is useful. Such substrates often have convincing specifications for optical transmittance, flatness and minimum birefringence, and should preferably have resistance to gas and solvent transmission. Mechanical properties such as warpage, impact resistance, hardness and scratch resistance are also important considerations. Glass or quartz sheets have been widely used in displays because these materials meet optical and flatness requirements and have excellent heat resistance, chemical resistance and barrier properties, but these materials have some desired mechanical properties, most notably low density, There is a disadvantage in that it does not have warpage and impact resistance.

As mentioned above, due to the mechanical limitations of glass or quartz sheets for application to optical or display devices, various plastics can be formed into lighter, thinner sheets or even film materials and because of their greater resistance to breakage. Have been proposed as alternative substrates. However, although plastic sheets have greater warpage than glass or quartz sheets of the same thickness, are more resistant to breakage and lighter, they have plastic sheets with the necessary optical specifications needed for use in optical and display applications. It is very difficult to manufacture at economical prices. Moreover, many types of plastic sheets suffer from unacceptable dimensional deformation when performed with respect to substrate processing conditions, especially temperature, during the manufacture of the display. That is, in order to provide sufficient thermal stability during the manufacturing process of the display device, a high temperature plastic (Tg of at least 150 ° C.) is preferable. Such materials include, for example, thermoplastic resins such as polyacrylates, polysulfones, polycarbonates and polyimides.

U.S. Patent 4,802,742 discloses the use of certain plastics such as polyether sulfones and polycarbonates as plastic substrate materials for LCDs. Polyether sulfone has a Tg of 220 ° C. and is therefore preferred for use as a substrate material over other plastics, but this resin is yellowish brown and therefore limited to thin film applications. In addition, polycarbonate is lighter in color and has a greater white light transmittance than polyether sulfone, but has a disadvantage in that Tg is undesirably low (150 ° C.) and has a relatively high stress-optic coefficient, resulting in high birefringence.

Meanwhile, in the case of a flexible substrate, a conductive oxide thin film of indium tin oxide (ITO) was manufactured and used by electron beam deposition or sputtering using materials such as polyester and polycarbonate. However, in the case of polyester, there are various applications to the substrate in the form of a sheet, but there is a problem in the transmittance in the visible light region (about 80%), and in the case of polycarbonate, the transmittance is higher than 90%, but in the form of a sheet In manufacturing, there is a problem of workability and high cost.

For example, Korean Laid-Open Patent Publication No. 2000-75332 includes a base film; Polyimide (PI), polyamide-imide (PAI), polyether-ether-ketone (PEEK), perfluoroalkoxy (PFA), polyphenylene sulfide (PPS) formed on at least one surface of the base film A heat resistance improving polymer film selected from the group consisting of; Although a plastic substrate for a liquid crystal display device including a protective film formed on at least one surface of the heat resistance improving polymer film is disclosed, it has a low permeability and has disadvantages in economical manufacturing.

In order to solve the above problems, the inventors have conducted extensive research, and in the polyester substrate polymerized with terephthalic acid (TPA) and ethylene glycol (EG), a certain amount of EG is replaced with cyclohexanedimethanol (CHDM). Thus, a method of manufacturing a conductive oxide thin film using an amorphous polyethylene terephthalate glycol (PETG) plastic substrate having improved transparency, processability, and physical properties by preventing crystallization was found, and the present invention was completed based on this.

Accordingly, an object of the present invention is to provide a method for producing a conductive oxide thin film using a PETG substrate having excellent transmittance and low surface resistance.

The method of the present invention for achieving the above object is made of a sheet having a thickness of 100 to 400㎛ using polyethylene terephthalate glycol (PETG) containing less than 30 mol% cyclohexanedimethanol (CHDM) based on the total glycol component ITO (Indium Tin) through RF plasma sputtering deposition at substrate pressure of 1-20mTorr and substrate temperature 25-150 ℃, or electron beam deposition using roll-to-roll at roller speed of 0.1-100m / min. Oxide) is deposited.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.                     

The present invention relates to a method for producing a conductive oxide thin film using a PETG plastic substrate, and more particularly, polyethylene terephthalate glycol (PETG) containing 30 mol% or less of cyclohexanedimethanol (CHDM) based on the total glycol component. The present invention relates to a method of manufacturing a conductive oxide thin film having excellent transmittance and low surface resistance by depositing an indium tin oxide (ITO) thin film on a used plastic substrate.

The flexible plastic substrate according to the present invention is manufactured according to the method disclosed in Korean Patent Application No. 2000-57353. According to the method, a modified polyester is provided in which the total glycol component, including ethylene glycol and 1,4-cyclohexanedimethanol, in a molar ratio of 1.3 to 3 in molar ratio with respect to terephthalic acid, is 30 mol% based on the total glycol component. The following 1, 4- cyclohexane dimethanol is included. The polyester resin provided according to the above method can provide an amorphous PETG plastic substrate having improved crystallinity and improved physical properties by preventing crystallization by replacing 30 mol% or less of CHDM with CHDM. The substrate is preferably in the form of a sheet having a thickness of about 100 ~ 400㎛, it is possible to improve the surface properties through the plasma surface treatment.

Surface modification is performed using a device as shown in FIG. 1 below. The PETG substrate is placed in the substrate support 11 in the vacuum chamber 10 and the argon gas is injected through the inlet 12 to maintain the gas pressure at about 5 mTorr. Plasma treatment for about 10 minutes changes the PETG substrate surface to improve adhesion.

Reactive oxygen and argon are injected into the injection hole 12 at a ratio of about 1: 10 to the ITO compound target by using an RF magnetron sputtering deposition method in an in-situ process on the surface-modified PETG substrate as described above. At this time, the ITO thin film is deposited while changing the process pressure to 1 to 20 mTorr. At this time, if the process pressure is less than 1 mTorr, the deposition rate is very low, and a considerable time is required to deposit a film having a desired thickness. There exists a considerable amount in the ITO thin film, surface resistance value rises and permeability falls. Preferred substrate temperatures for the present invention are from room temperature (25 ° C.) to 150 ° C .. At this time, if the temperature of the substrate exceeds 150 ° C., a good quality ITO thin film cannot be obtained by sublimation by oligomers of the PETG substrate itself. Its flatness makes it difficult to deposit uniform ITO thin films.

In addition, in the case of a roll-to-roll (web coating) process in which ITO can be deposited in a batch process in the form of PETG in a roll, the apparatus as shown in FIG. A PETG roll with a length of about 50 to 100 m and a width of about 600 mm x 1200 mm is placed on the substrate roller 21, and the surface treatment 22 using ions is first applied while tensioning the roller with a constant force. By varying from 0.1 to 100 m / min, an ITO thin film is deposited on a PETG substrate by electron beam evaporation of an ITO compound under oxygen plasma conditions at the location of a cooling drum 23. The slower the roller, the better the surface resistance value, but the lowest value in the transmittance. When the speed of the roller is 100m / min or more, the thickness of the ITO thin film is so thin that the surface resistance value is large, which is not preferable.

Methods usable for the production of indium tin oxide (ITO) conductive oxide thin films of the present invention include methods such as plasma sputtering, ion beam sputtering, RF plasma sputtering, magnetron sputtering and electron beam deposition.

PETG substrate according to the present invention exhibits a surface resistance value of about 100 ~ 400 Ω / ㎠, transmittance of 90% or more in the visible light region is applied to a display device such as a touch panel or a plastic LCD through the electron beam deposition method or sputtering method It is useful to manufacture an indium tin oxide (ITO) conductive oxide film.

Hereinafter, the present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the scope of the present invention is not limited thereto.

Examples 1-5 and Comparative Examples 1-4

Process pressure is changed by using PETG substrate (Eske Chemical Co., Ltd., SKYGREEN S2008) as shown in Table 1 while plasma surface treatment in the vacuum chamber as shown in FIG. 1 and then using ITO compound target by RF magnetron sputtering method After the deposition of the ITO thin film and measuring its properties while changing to 1, 5, 10, 15, 20 and 25mTorr, the results are shown in Table 1 below. In addition, the characteristics of the ITO deposition on PET and ITO film on PETG to compare the characteristics of the product characteristics of the major ITO plastic manufacturers in Table 2 below.

division Process pressure (mTorr) Surface resistance (Ω / ㎠) Permeability (%) Addhesion (%) Example 1 One 250 ± 10 ≥95 100 Example 2 5 270 ± 10 ≥92 100 Example 3 10 300 ± 10 ≥92 100 Example 4 15 330 ± 10 ≥92 100 Example 5 20 350 ± 10 ≥92 100 Comparative Example 1 25 500 ± 10 ≥82 100

Major companies Plastic substrate Permeability (%) Surface resistance (Ω / ㎠) Addhesion (%) Comparative Example 2 Nitto Denko PET ≥80% 400 ± 50 100 Comparative Example 3 OIKE PET ≥80% 200-500 100 Comparative Example 4 Sheldahl PET ≥87% 60 to 400 100

As shown in the Examples and Comparative Examples, in the case of the oxide thin film obtained by depositing at a process pressure of 1 to 20 mTorr using PETG according to the present invention, the oxide thin film and the PET substrate obtained by depositing under a process pressure outside the scope of the present invention. Compared with the oxide thin film obtained by using the present invention, an ITO plastic having excellent permeability and significantly improved surface resistance value could be obtained.

Examples 6-8

Except that the temperature of the substrate was changed to 25 ℃ to 75 ℃ was subjected to ITO thin film deposition in the same manner as in Example 1, after measuring its properties, the results are shown in Table 3 below.

division Substrate temperature (℃) Surface resistance (Ω / ㎠) Permeability (%) Addhesion (%) Example 6 25 250 ± 10 ≥95 100 Example 7 50 250 ± 10 ≥95 100 Example 8 75 200 ± 10 ≥92 100

Examples 9-11

Except for changing the temperature of the substrate from 100 ℃ to 150 ℃ ITO thin film deposition was carried out in the same manner as in Example 2 and after measuring its properties, the results are shown in Table 4 below.                     

division Substrate temperature (℃) Surface resistance (Ω / ㎠) Permeability (%) Addhesion (%) Example 9 100 270 ± 10 ≥92 100 Example 10 125 300 ± 10 ≥92 100 Example 11 150 300 ± 10 ≥90 100

As shown in the above embodiment, it was found that even when deposition was performed while changing the temperature of the substrate from 25 ° C. to 150 ° C., it had a significantly increased surface resistance value and transmittance compared to the ITO plastic using the conventional PET as the substrate.

Examples 12-17

After the ion surface treatment in the roll-to-roll process shown in FIG. 2 using a PETG substrate, the ITO thin film was deposited by measuring the speed of the roller to 0.1 to 100 m / min by an electron beam deposition method to measure its characteristics. The results are shown in Table 5 below.

division Roller speed (m / min) Surface resistance (Ω / ㎠) Permeability (%) Width (mm) Example 12 0.1 220 ± 10 ≥92 600 Example 13 2 250 ± 10 ≥92 600 Example 14 4 275 ± 10 ≥92 600 Example 15 6 300 ± 10 ≥95 600 Example 16 50 320 ± 10 ≥95 600 Example 17 100 350 ± 10 ≥95 600

As described above, in contrast to conventional thin films using PET, an oxide thin film using PETG, which is an amorphous polyester resin in which a certain amount of EG is replaced with CHDM, is used as a polymer substrate in the polyester according to the present invention. It exhibits a lower surface resistance value and can be applied to display elements for touch panels and plastic LCDs.

Claims (3)

Process pressure 1-20 mTorr and substrate temperature on a substrate made of 100-400 μm thick sheets using polyethylene terephthalate glycol (PETG) containing up to 30 mol% cyclohexanedimethanol (CHDM) based on the total glycol components. Indium Tin Oxide (ITO) thin film is deposited by RF plasma sputtering deposition at 25 to 150 ° C. or electron beam deposition using roll-to-roll at a roller speed of 0.1 to 100 m / min. Method for producing an oxide thin film. The method of manufacturing a conductive oxide thin film according to claim 1, wherein the sheet width of the substrate used in the roll-to-roll process is 600 to 1200 mm, and the length of the sheet wound on the roll is 50 to 100 m. A plastic substrate on which the conductive oxide thin film according to claim 1 is deposited, having a surface resistance of 100 to 400 mW / cm 2 and a transmittance of 90% or more in the visible light region.

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