KR102130704B1 - Polyester film and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an antistatic polyester film, which has a lower surface resistance than a conventional polyester film, and relates to a polyester film coated with a conductive polymer antistatic agent used for packaging, electronic material processing, and product protection, and a method for manufacturing the same. .

Description

Polyester film and its manufacturing method{POLYESTER FILM AND MANUFACTURING METHOD THEREOF}

The present invention relates to an antistatic treated polyester film, a packaging film having a lower surface resistance than a conventional polyester film, an electronic material process, a conductive polymer antistatic agent used for product protection and a coated polyester film and a method for manufacturing the same will be.

The antistatic polyester film produced by the production method of the present invention has excellent solvent resistance and excellent adhesion and bonding strength to the silicon layer used in the subsequent process.

In recent years, with the rapid development of various electronic, electrical and information communication fields, problems caused by static electricity have occurred in many fields, ranging from industrial products to household products to which they are applied, and antistatic functions in these devices and sites are emerging as essential functions. . Antistatic refers to discharging the electric charge accumulated on the surface of the insulator in an appropriate manner. The reason for requiring such antistatic property is that, in the film manufacturing process or the film processing process, static electricity is generated to attach dust or foreign matter to the product, and a discharge phenomenon is generated, thereby causing a flamming risk when using an organic solvent. Therefore, it is an essential requirement to impart antistatic performance.

In order to impart such antistatic performance, an antistatic layer is formed on a film. When the crosslink density of the binder resin used to form the antistatic layer is low, defects may occur due to damage to the coating film by the solvent used in the post process. There is a possibility. Therefore, there is a need to improve the solvent resistance of the binder resin forming the antistatic layer, and there is a need for an antistatic layer having excellent adhesion and bonding strength with a silicone release layer used in a subsequent process.

Korean Registered Patent No. 10-0902033 (2009.06.03)

The present invention is to provide a polyester film having an antistatic coating layer having excellent solvent resistance, excellent adhesion and bonding strength with a silicone release layer used in a subsequent process, and excellent surface resistance, and a method for manufacturing the same.

The present invention for achieving the above object is as follows.

The present invention is a polyester film comprising a base layer made of a polyester resin and an antistatic layer laminated on one or both sides of the base layer,

The antistatic layer is formed by coating and drying an aqueous coating composition comprising a binder composition and water,

The binder composition relates to a polyester film comprising a conductive polymer resin selected from polythiophene or a polythiophene derivative and a water-dispersible polyester resin.

In addition, the present invention

a) melt extrusion of the polyester resin to produce a polyester sheet;

b) stretching the polyester sheet in the machine direction;

c) an aqueous coating composition comprising a binder composition obtained by mixing a conductive polymer resin selected from polythiophene or a polythiophene derivative and a water-dispersible polyester resin and water on one or both sides of the polyester film stretched in the machine direction. After coating, stretching in the transverse direction; And

d) heat-setting the biaxially stretched polyester film;

It relates to a method for producing a polyester film comprising a.

The polyester film according to the present invention has an antistatic property on the coating surface, prevents overlapping due to static electricity between the films during off-sheet work, and has an effect of preventing problems caused by static electricity in the applied product.

In addition, the antistatic layer has excellent antistatic performance, solvent resistance, excellent adhesion to the silicone layer, adhesiveness to tape, printability, and one side of the base layer on which the antistatic layer is not formed is adhesive and printable. Have a surname In particular, the solvent resistance to solvents such as methyl ethyl ketone, toluene, ethyl acetate, ethanol, and isopropyl alcohol is very excellent, and there is an effect of freely selecting a solvent in a subsequent process.

The following will be described with reference to one aspect for a detailed description of the present invention, the present invention is not limited thereto.

The present inventors have studied to form an antistatic coating layer having excellent solvent resistance, and have found that the solvent resistance can be improved by forming an antistatic layer using an aqueous coating composition with a water dispersible polyester binder having excellent crosslinking density. By mixing and using a water-dispersible polyester binder resin that satisfies specific properties with a high crosslinking density and a high glass transition temperature, so as to have excellent compatibility with a conductive polymer resin used for antistatic properties, by an inline coating process. It is possible to form an antistatic layer, and the present invention was found by providing a film having excellent antistatic properties having a surface resistance of 10 ⁵ ~ 10 ⁹ Ω/sq, more preferably 10 ⁶ ~ 10 ⁸ Ω/sq. Completed.

In addition, the inventors of the present invention improve the miscibility of the water-dispersible polyester binder resin and the conductive polymer resin in order to further satisfy the properties of the surface resistance of 10 ⁵ ~ 10 ⁹ Ω/sq while further reducing the thickness of the antistatic layer, It is necessary to further lower the viscosity, and as a result of this study, when a polyester binder resin and a conductive polymer resin were mixed, a pH adjusting agent was added to mix in a pH range atmosphere of the water-dispersible polyester binder resin, and a silicone-based or fluorine-based leveling agent. , It was found that the viscosity of the water-based coating composition can be lowered by adding an alcohol-based solvent or a mixture thereof, and the present invention was completed by discovering that the adhesion to silicone is further improved by using a silicone-based leveling agent.

One aspect of the present invention is a polyester film comprising a base layer made of a polyester resin and an antistatic layer laminated on one or both sides of the base layer,

The antistatic layer is formed by coating and drying an aqueous coating composition comprising a binder composition and water,

The binder composition is a polyester film comprising a conductive polymer resin selected from polythiophene or a polythiophene derivative and a water-dispersible polyester resin.

In one aspect of the present invention, the antistatic layer may have a thickness of 0.03 to 0.05% relative to the total film thickness, and a surface resistance in the thickness range of 10 ⁵ to 10 ⁹ Ω/sq.

In one embodiment of the present invention, the water-dispersible polyester resin may have a glass transition temperature of 50 to 120°C, an acid value of 5 mgKOH/g or less, a refractive index of 1.5 to 1.7, and a molecular weight of 15000 to 30000.

In one aspect of the present invention, the water-based coating composition may have a viscosity of 2 to 5 cps (25°C).

In one embodiment of the present invention, the binder composition may be that the water-dispersible polyester resin is 30 to 40% by weight, and the conductive polymer resin is 60 to 70% by weight.

In one aspect of the present invention, the binder composition may further include 0.1 to 10% by weight of any one or more additives selected from pH adjusting agents, alcohol-based solvents, silicone-based or fluorine-based leveling agents.

In one aspect of the present invention, the water-based coating composition may further include any one or more additives selected from a wetting agent, a particle, a slip agent, a crosslinking agent, and a curing agent.

In one aspect of the present invention, the antistatic layer may be coated by an inline coating method.

In one aspect of the present invention, the antistatic layer may have a dry coating thickness of 10 to 500 nm.

In one embodiment of the present invention, the polyester film may have a total thickness of 12 ~ 250㎛.

In one embodiment of the present invention, the anti-static layer is one that is left to stand for 30 minutes in an atmosphere having a temperature of 25°C and a humidity of 50% after laminating on a silicon layer, and then has a peel strength of 1.5 to 3 gf/inch measured by a 180 degree peel test. Can.

In addition, the present invention relates to a method of manufacturing a polyester film, one aspect of the method of manufacturing

a) melt extrusion of the polyester resin to produce a polyester sheet;

b) stretching the polyester sheet in the machine direction;

c) an aqueous coating composition comprising a binder composition obtained by mixing a conductive polymer resin selected from polythiophene or a polythiophene derivative and a water-dispersible polyester resin and water on one or both sides of the polyester film stretched in the machine direction. After coating, stretching in the transverse direction; And

d) heat-setting the biaxially stretched polyester film;

It includes.

In one aspect of the polyester film of the present invention, the binder composition may be one containing 30 to 40% by weight of the water-dispersible polyester resin and 60 to 70% by weight of the conductive polymer resin.

In one aspect of the polyester film of the present invention, the binder composition may further include 0.1 to 10% by weight of any one or more additives selected from pH adjusting agents, alcohol solvents, silicone-based or fluorine-based leveling agents.

In one aspect of the polyester film of the present invention, the water-based coating composition may have a viscosity of 2 to 5 cps (25°C).

In one aspect of the polyester film of the present invention, the machine direction stretching may be 3 to 4 times stretching at 70 to 110°C, and the transverse direction stretching may be 3 to 4.5 times stretching at 110 to 240°C.

In one aspect of the polyester film of the present invention, the heat setting may be performed at 220 ~ 240 ℃.

Hereinafter, each configuration of one aspect of the present invention will be described in more detail.

The present invention is characterized by forming an antistatic layer for imparting antistatic performance on one or both sides of a polyester film by an inline coating method.

When the antistatic layer is applied offline on the polyester film to form it, there is a problem in that the cost increases because the process is additionally increased, and the cost increases compared to the inline coating method because the coating thickness becomes thicker. Therefore, the present inventors are applied by an in-line coating method, and by applying a water-based coating composition for drying and curing in the stretching process to form an antistatic layer, the coating thickness is thin, and the adhesion with the polyester film is excellent, It has excellent resistance to moisture and solvents.

In the present invention, the base layer may be a film made of a polyester resin, and more specifically, polyethylene terephthalate or polyethylene naphthalate. More preferably, it is preferable to use polyethylene terephthalate having an intrinsic viscosity in the range of 0.6 to 0.7, since it has excellent weather resistance and hydrolysis resistance.

The thickness of the substrate layer is not limited, preferably 12 to 250 μm, and the thickness of the polyester film of the present invention is not limited, but the total thickness including the substrate layer and the antistatic layer The production of 12 ~ 250㎛ is advantageous, since it is possible to implement various lamination structures.

In addition, corona treatment may be applied to the opposite surface of the polyester film, which is an antistatic coating layer, to provide printability.

In the present invention, the antistatic layer is formed by coating and drying an aqueous coating composition comprising a binder composition in which a conductive polymer resin selected from polythiophene or a polythiophene derivative, a water-dispersible polyester resin, and water are mixed, and dried. It is coated by a coating method.

In order to be capable of in-line coating, it should be a water-based composition, and when it is made of a water-based composition, there is a problem that durability is weakened against moisture or a solvent in a post process, but the inventors of the present invention mix a specific water-dispersible polyester resin with a conductive polymer resin. As it was used, the present invention was completed by discovering that in-line coating is possible, but the physical properties of the formed antistatic coating layer are excellent, water resistance and durability are excellent, and thus, physical properties equivalent to or more than those of the existing offline coating can be expressed.

The antistatic layer may have a dry coating thickness of 0.03 to 0.05% of the total film thickness, and a surface resistance in the thickness range of 10 ⁵ to 10 ⁹ Ω/sq, more preferably 10 ⁶ to 10 ⁸ Ω/sq. have. That is, when the total film thickness is 100㎛, the antistatic layer may have a dry coating thickness of 30 ~ 50nm. It is suitable to apply as a base film such as ITO process in the range of surface resistance of 10 ⁵ ~ 10 ⁹ Ω/sq.

More specifically, the antistatic layer preferably has a dry coating thickness of 10 to 500 nm, more preferably 30 to 150 nm, and the polyester film preferably has a total thickness of 12 to 250 μm. When the dry coating thickness of the antistatic layer is less than 10 nm, the surface resistance may be high, and when it exceeds 500 nm, the cost may increase, and the viscosity may increase, resulting in poor processability.

In one embodiment of the present invention, the water-based coating composition comprises a conductive polymer resin selected from polythiophene or a polythiophene derivative, a binder composition in which water-dispersible polyester resin is mixed, and water.

The binder composition may be 30 to 40% by weight of water-dispersible polyester resin, and 60 to 70% by weight of conductive polymer resin, but is not limited thereto. When the water-dispersible polyester resin is used in an amount of less than 30% by weight, the solvent resistance may deteriorate, and when it exceeds 40% by weight, the content of the conductive polymer resin is relatively low, so the surface resistance may be lowered.

The water-based coating composition is not limited, but it is preferable because it is possible to easily form a coating layer with a thin coating thickness when inline coating in the range of viscosity of 2 to 5 cps (25°C), and maintaining the viscosity. In order to be necessary, the binder composition may further include any one or more additives selected from pH adjusting agents, alcohol-based solvents, silicone-based or fluorine-based leveling agents. The additive is not limited, but is preferably used in an amount of 0.1 to 10% by weight.

The pH adjusting agent is used to improve the miscibility of the water-dispersible polyester resin and the conductive polymer resin, and to lower the viscosity of the composition, and the pH range is preferably adjusted according to the pH range of the water-dispersible polyester resin. As the pH adjusting agent, ammonium hydroxide, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide (TBAH), or the like can be used.

The alcohol-based solvent is used to lower the viscosity of the composition as a quick-drying solvent, but is not limited thereto, and specifically, for example, isopropyl alcohol, n-propanol, ethanol, methanol, and the like can be used.

When the silicone-based or fluorine-based leveling agent is applied with a silicone adhesive on the anti-static layer, it is used to improve the bonding strength between the anti-static layer and the silicone adhesive, and to lower the viscosity of the composition, but is not limited thereto, specifically, for example, water-based Additives for silicone surfaces for paints and printing inks can be used. Commercialized examples include BYK's BYK-325, BYK-330, BYK-331, BYK-333, and BYK-335, but are not limited thereto.

The water-dispersible polyester resin has a glass transition temperature of 50 to 120°C, an acid value of 5 mgKOH/g or less, a refractive index of 1.5 to 1.7, and a molecular weight of 15000 to 30000, which has high crosslinking degree to achieve the desired solvent resistance. It is preferable because it can be done. Commercialized examples of the water-dispersible polyester resin may be used, such as RZ-105, Z-561, Z-687, Z-565, RZ-570 of Goo, but is not limited thereto.

When the glass transition temperature of the water-dispersible polyester resin is less than 50°C, the crosslinking density is low, so solvent resistance is insufficient, and when it exceeds 120°C, stretchability may deteriorate, and solvent resistance and stretchability appear in the above range. desirable.

In addition, when the acid value exceeds 5 mgKOH/g, the liquid stability of the raw material may be deteriorated, and the liquid stability of the raw material is good in a range of 5 mgKOH/g or less, which is preferable.

In addition, when the refractive index is less than 1.5, a rainbow phenomenon appears on the film, and when it is more than 1.7, elongation and adhesiveness may deteriorate, and a rainbow phenomenon does not appear in the above range, and elongation and adhesiveness are excellent. .

In addition, when the molecular weight is less than 15000, a blocking problem may occur, and when it is more than 30000, compatibility with a conductive polymer may be deteriorated, and blending with a conductive polymer in the above range is preferable because of excellent liquid stability.

The conductive polymer resin is used to impart antistatic properties, and may include a polythiophene or a polythiophene derivative. More preferably, an aqueous dispersion of polyanion and polythiophene or an aqueous dispersion of polyanion and polythiophene derivative can be used. The polyanion is an acidic polymer, and is a polymer carboxylic acid or polymer sulfonic acid, polyvinyl sulfonic acid, and the like. Examples of the polymer carboxylic acid include polyacrylic acid and polymethacrylic acid, and the polymer sulfonic acid includes polystyrene sulfonic acid. For polythiophene or polythiophene derivatives, polyanions are preferably present in excess at a solids weight ratio, from the viewpoint of conductivity, and the polyanion is more than 1% by weight relative to 1% by weight of the polythiophene or polythiophene derivative, 3 It is preferably less than weight percent.

In one aspect of the present invention, the water-based coating composition may further include any one or two or more additives selected from a wetting agent, a particle, a slip agent, a crosslinking agent, and a curing agent as necessary.

The wetting agent is used to uniformly apply the water-based coating composition on the polyester film, and it is preferable to use one selected from polyethylene glycol, polyethylene ester, modified silicone, fluorine mixture, etc., since the coating property is very improved. It is preferable to use 0.1 to 0.5% by weight since silver has excellent adhesion.

The crosslinking agent is used to improve solvent resistance, and specifically, for example, any one or more compounds selected from the group consisting of block isocyanate-based, carbodiimide-based, oxazoline-based, epoxy-based, and melamine-based may be used. have. The content is preferably 0.1 to 10% by weight, more preferably 0.1 to 0.5% by weight. When used at less than 0.1% by weight, solvent resistance may be deteriorated, and when used at more than 10% by weight, surface resistance may not appear.

Also, if necessary, particles may be added to improve the blocking property of the coating layer using an emulsion, and inorganic particles, organic particles, and the like may be added. It is preferable to use the content of 0.01 to 10% by weight.

In addition, additives such as UV stabilizers, slip agents, and curing agents commonly used in the field may be further added as necessary.

As a method for preparing the water-based coating composition, first, a conductive polymer resin and a water-dispersible polyester resin are mixed to prepare a binder composition, and then water is added to the binder composition to prepare an emulsion-type water-based coating composition. desirable.

More preferably, in order to lower the viscosity of the water-based coating composition so that the coating thickness and coating properties are better, when mixing the binder composition, any one or more additives selected from pH adjusting agents, alcohol-based solvents, silicone-based or fluorine-based leveling agents are further mixed. After mixing, it is preferable to prepare an aqueous coating composition in the form of an emulsion by adding water.

Next, the method for producing the polyester film of the present invention

a) melt extrusion of the polyester resin to produce a polyester sheet;

b) stretching the polyester sheet in the machine direction;

c) an aqueous coating composition comprising a binder composition obtained by mixing a conductive polymer resin selected from polythiophene or a polythiophene derivative and a water-dispersible polyester resin and water on one or both sides of the polyester film stretched in the machine direction. After coating, stretching in the transverse direction; And

d) heat-setting the biaxially stretched polyester film;

It includes.

In addition, after the step c), if necessary, further comprising the step of coating a polyacrylic resin or a polyurethane resin on the opposite surface on which the antistatic layer of the polyester film is formed, or after step d), the antistatic layer is formed. Corona treatment to the surface; may further include. When the polyacrylic resin or polyurethane resin is coated as described above, adhesiveness and printability may be further improved, and may be formed by an in-line coating method. The coating thickness is preferably a dry coating thickness of 30 ~ 150nm, more preferably 50 ~ 150nm.

The corona treatment is intended to further improve printability, and the corona treatment is not limited as long as it is a conventional method in the art.

The step a) is a process of manufacturing a sheet through a T-die by melt-extruding a resin in a cylinder to produce a polyester film.

The step b) is a process for producing a polyester film by biaxially stretching a polyester sheet, and it is preferable that the machine direction stretching is performed using one or more rollers. More specifically, the machine direction stretching is preferably 3 to 4 times stretching at 70 to 110°C.

Next, in step c), an antistatic layer is formed by an in-line coating method, and at this time, it is preferable to use an aqueous dispersion that can be used for in-line coating. At this time, the composition of the coating composition for forming the antistatic layer is the same as described above, and it is preferable to apply such that the thickness of the dry coating after stretching is 10 to 500 nm and more preferably 30 to 150 nm after stretching. After applying the coating composition to form an antistatic layer, it is stretched in the transverse direction. At this time, it is preferable to use a tenter for transverse stretching. Specifically, the transverse stretching is preferably stretched 3 to 4.5 times at 110 to 240°C.

Next, a process of drying and heat setting is performed to remove moisture used in the antistatic layer, cure the antistatic layer, and prevent the film from shrinking. In the heat setting process, the antistatic layer may be dried and cured, and preferably, it is performed at 220 to 240°C.

In addition, it is preferable to perform 2 to 10% relaxation in the machine direction and in the transverse direction at 150 to 200°C after the heat setting.

The following will be described as an example for a detailed description of the present invention, the present invention is not limited to the following examples.

Hereinafter, the physical properties of the present invention were measured as follows.

1) Surface resistance

The surface resistance of the antistatic layer of the present invention was evaluated. The measurement method is Mitsubishi Chemical Corp. Using Hiresta-Up MCP-HP450 equipment, the surface resistance was measured under conditions of 25°C, 50%Rh, 10 V, and 10 seconds.

The surface resistance before stretching was measured in the state of forming an antistatic layer with a thickness of 50 nm on the surface of the polyethylene terephthalate film,

The surface resistance after stretching is a measurement of the surface resistance of a film produced by forming an antistatic layer by an in-line coating method during film production as in Examples and Comparative Examples, followed by stretching.

2) Solvent resistance

The solvent resistance of the antistatic layer of the present invention was evaluated.

The measurement method was to place a metal plate with a width of 25 mm X 25 mm and a weight of 915 g on a microfiber cloth buried with methyl ethyl ketone, toluene, ethyl acetate, ethanol, and isopropyl alcohol, and rub it 10 times. Surface resistance was measured in the same manner as the method.

The solvent resistance evaluation was evaluated based on the following criteria by calculating the difference between the surface resistance measured by the surface resistance method before stretching in item 1) and the surface resistance measured after rubbing with the solvent.

◎: When there is no change in antistatic properties

○: When the antistatic change was 10 ¹ Ω/sq or less

△: When the antistatic sex change 10 ¹ Ω / sq or less than 10 ² Ω / sq

×: When the antistatic property disappears

3) Viscosity

The viscosity of the water-based coating composition was measured using a Brookfield viscosity meter (Disital viscometer, UL Adapter, LVDV2T), and the viscosity was measured using 61 spindles while stirring at 25°C at 30 rpm.

4) Silicone adhesion evaluation

After corona treatment on one side of the polyethylene terephthalate film, a silicone adhesive (Dabo C&M, DVS-1L) was applied to the corona-treated side and dried at 150° C. for 4 minutes to form a 15 μm thick silicone coating layer.

After the antistatic layer of the polyester film formed with the antistatic layer prepared in Examples and Comparative Examples was laminated so that the silicone coating layer faced each other, it was pressed twice with a 2 kg rubber roll. At this time, the lower side became an antistatic layer, and the silicon coating layer was stacked on top of it to make it laminated.

Cut the laminated samples at 1-inch intervals, prepare 3 samples, leave them in a constant temperature and humidity room (25°C, 50% humidity) for 30 minutes, and then take them out and evaluate them with a 180 degree peel tester (AR-1000).

At this time, the measurement condition is 30cm/min. It was 1 inch.

5) Coating properties

<Coating property of film before stretching>

The coating property was evaluated in a state where an antistatic layer was formed with a thickness of 50 nm on the surface of the polyethylene terephthalate film.

The coating appearance level under a fluorescent lamp was evaluated based on the naked eye.

○: No pinhole and the coating surface is clean

×: Opaque due to the occurrence of pinholes and cloudiness on the coated surface as a whole.

<Coating property of film after stretching>

As in Examples and Comparative Examples, an anti-static layer was formed by an in-line coating method during film production, and then stretched to evaluate the coating properties of the produced film.

The coating appearance level of the film stretched under a fluorescent lamp was evaluated based on visual inspection.

○: No pinhole and the coating surface is clean

×: Opaque due to the occurrence of pinholes and cloudiness on the coated surface as a whole.

[Example 1]

1) Preparation of binder composition (1)

Water dispersible polyester resin (Goo, RZ-105, solid content 25% by weight, pH 5-7, glass transition temperature 52°C, acid value below 5 mgKOH/g, refractive index 1.56, molecular weight 16000), and conductive polymer resin (( Note) Suyang Chemtech Co., Ltd., SY-CP-E421A) was mixed at a weight ratio of 40:60 to prepare a binder composition (1). The viscosity of the prepared binder composition (1) was 28.8 cps (25°C).

2) Preparation of water-based coating composition (1)

The aqueous binder composition (1) was prepared by mixing 10% by weight of the prepared binder composition (1), 0.4% by weight of a wetting agent (ZonylFSH from DuPont), and 89.6% by weight of water. The prepared aqueous coating composition (1) had a viscosity of 4.8 cps (25° C.).

3) Preparation of polyester film

A polyethylene terephthalate chip having a moisture content of 100 ppm or less was injected into a melt extruder, melted, and then extruded through a T-die, rapidly cooled and solidified with a casting drum having a surface temperature of 20°C to prepare a polyethylene terephthalate sheet having a thickness of 2000 µm. .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110° C., and then cooled to room temperature. Thereafter, the water-based coating composition (1) was coated on one surface by a bar coating method, and then preheated and dried at 140° C. and stretched 3.5 times in the transverse direction (TD). Subsequently, heat treatment was performed at 235° C. in a 5-stage tenter, and heat-set at 200° C. by relaxing 10% in the machine direction and the transverse direction to prepare a 100 μm biaxially stretched film having an antistatic layer formed on one side. The thickness of the dry coating after stretching of the antistatic layer was 50 nm.

The physical properties of the film thus obtained are shown in Table 1 below.

[Example 2]

1) Preparation of binder composition (2)

Water-dispersible polyester resin (Goo, Z-687, solid content 25% by weight, pH 5-7, glass transition temperature 110°C, acid value below 5 mgKOH/g, refractive index 1.61, molecular weight 26000), and conductive polymer resin (( Note) Suyang Chemtech Co., Ltd., SY-CP-E421A) was mixed at a weight ratio of 40:60 to prepare a binder composition (2). The viscosity of the prepared binder composition (2) was 27 cps (25°C).

2) Preparation of water-based coating composition (2)

10% by weight of the prepared binder composition (2), a wetting agent (ZonylFSH from DuPont) 0.4% by weight, and 89.6% by weight of water were mixed to prepare an aqueous coating composition (2). The prepared aqueous coating composition (2) had a viscosity of 4.5 cps (25°C).

3) Preparation of polyester film

A polyethylene terephthalate chip having a moisture content of 100 ppm or less was injected into a melt extruder, melted, and then extruded through a T-die, rapidly cooled and solidified with a casting drum having a surface temperature of 20°C to prepare a polyethylene terephthalate sheet having a thickness of 2000 µm. .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110° C., and then cooled to room temperature. Thereafter, the water-based coating composition (2) was coated on one side by a bar coating method, preheated at 140° C., dried, and stretched 3.5 times in the transverse direction (TD). Subsequently, heat treatment was performed at 235° C. in a 5-stage tenter, and heat-set at 200° C. by relaxing 10% in the machine direction and the transverse direction to prepare a 100 μm biaxially stretched film having an antistatic layer formed on one side. The thickness of the dry coating after stretching of the antistatic layer was 50 nm.

The physical properties of the film thus obtained are shown in Table 1 below.

[Example 3]

1) Preparation of binder composition (3)

Water dispersible polyester resin (Goo, RZ-105, solid content 25% by weight, pH 5~7, glass transition temperature 52°C, acid value below 5 mgKOH/g, refractive index 1.56, molecular weight 16000), impurity ion removal reinforced product Conductive Polymer Resin (Suyang Chemtech Co., Ltd., SY-CP-E421M) mixed with a weight ratio of 40:60, 95% by weight of a binder resin, and tetraethylammonium hydroxide (TEAH) as a pH adjusting agent to add a pH of 6 After being adjusted as much as possible, a binder composition (3) was prepared by mixing 4.9% by weight of isopropyl alcohol and 0.1% by weight of a silicone leveling agent (BYK, BYK-333). The viscosity of the prepared binder composition (3) was 15.6 cps (25°C).

2) Preparation of water-based coating composition (3)

The aqueous binder composition (3) was prepared by mixing 10% by weight of the prepared binder composition (3), 0.4% by weight of a wetting agent (ZonylFSH from DuPont), and 89.6% by weight of water. The prepared aqueous coating composition (3) had a viscosity of 2.6 cps (25° C.).

3) Preparation of polyester film

A polyethylene terephthalate chip having a moisture content of 100 ppm or less was injected into a melt extruder, melted, and then extruded through a T-die, rapidly cooled and solidified with a casting drum having a surface temperature of 20°C to prepare a polyethylene terephthalate sheet having a thickness of 2000 µm. .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110° C., and then cooled to room temperature. Thereafter, the water-based coating composition 3 was coated on one surface by a bar coating method, and then preheated and dried at 140° C. and stretched 3.5 times in the transverse direction (TD). Subsequently, heat treatment was performed at 235° C. in a 5-stage tenter, and heat-set at 200° C. by relaxing 10% in the machine direction and the transverse direction to prepare a 100 μm biaxially stretched film having an antistatic layer formed on one side. The thickness of the dry coating after stretching of the antistatic layer was 50 nm.

The physical properties of the film thus obtained are shown in Table 1 below.

[Example 4]

1) Preparation of binder composition (4)

Water-dispersible polyester resin (Goo, Z-687, solid content 25% by weight, pH 5-7, glass transition temperature 110°C, acid value below 5 mgKOH/g, refractive index 1.61, molecular weight 26000), impurity ion removal strengthened product Conductive Polymer Resin (Suyang Chemtech Co., Ltd., SY-CP-E421M) mixed with a weight ratio of 40:60, 95% by weight of a binder resin, and tetraethylammonium hydroxide (TEAH) as a pH adjusting agent to add a pH of 6 After being adjusted as much as possible, a binder composition (3) was prepared by mixing 4.9% by weight of isopropyl alcohol and 0.1% by weight of a silicone leveling agent (BYK, BYK-333). The viscosity of the prepared binder composition (4) was 13.6 cps (25°C).

2) Preparation of water-based coating composition (4)

10% by weight of the prepared binder composition (4), a wetting agent (ZonylFSH from DuPont) 0.4% by weight, and 89.6% by weight of water were mixed to prepare an aqueous coating composition (4). The prepared aqueous coating composition (4) had a viscosity of 2.3 cps (25° C.).

3) Preparation of polyester film

A polyethylene terephthalate chip having a moisture content of 100 ppm or less was injected into a melt extruder, melted, and then extruded through a T-die, rapidly cooled and solidified with a casting drum having a surface temperature of 20°C to prepare a polyethylene terephthalate sheet having a thickness of 2000 µm. .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110° C., and then cooled to room temperature. Thereafter, the water-based coating composition 4 was coated on one surface by a bar coating method, and then preheated and dried at 140° C. and stretched 3.5 times in the transverse direction (TD). Subsequently, heat treatment was performed at 235° C. in a 5-stage tenter, and heat-set at 200° C. by relaxing 10% in the machine direction and the transverse direction to prepare a 100 μm biaxially stretched film having an antistatic layer formed on one side. The thickness of the dry coating after stretching of the antistatic layer was 50 nm.

The physical properties of the film thus obtained are shown in Table 1 below.

[Comparative Example 1]

1) Preparation of binder composition (5)

Water-dispersible polyurethane resin (DKS, H-3, solid content 22% by weight, pH 3-4, glass transition temperature 45°C, refractive index 1.53, molecular weight 8000), and conductive polymer resin (Sooyang Chemtech Co., Ltd., SY) -CP-E421A) was mixed at a weight ratio of 40:60 to prepare a binder composition (5). The prepared binder composition (5) had a viscosity of 27.5 cps (25°C).

2) Preparation of water-based coating composition (5)

The aqueous binder composition (5) was prepared by mixing 10% by weight of the prepared binder composition (5), 0.4% by weight of a wetting agent (ZonylFSH from DuPont), and 89.6% by weight of water. The viscosity of the prepared water-based coating composition (5) was 4.6 cps (25°C).

3) Preparation of polyester film

A polyethylene terephthalate chip having a moisture content of 100 ppm or less was injected into a melt extruder, melted, and then extruded through a T-die, rapidly cooled and solidified with a casting drum having a surface temperature of 20°C to prepare a polyethylene terephthalate sheet having a thickness of 2000 µm. .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110° C., and then cooled to room temperature. Thereafter, the water-based coating composition 5 was coated on one surface by a bar coating method, and then preheated and dried at 140° C. and stretched 3.5 times in the transverse direction (TD). Subsequently, heat treatment was performed at 235° C. in a 5-stage tenter, and heat-set at 200° C. by relaxing 10% in the machine direction and the transverse direction to prepare a 100 μm biaxially stretched film having an antistatic layer formed on one side. The thickness of the dry coating after stretching of the antistatic layer was 50 nm.

The physical properties of the film thus obtained are shown in Table 1 below.

[Comparative Example 2]

1) Preparation of binder composition (6)

Water-dispersible polyurethane resin (DKS, H-3, solid content 22 wt%, pH 3~4, glass transition temperature 45°C, refractive index 1.53, molecular weight 8000), impurity ion removal reinforced product conductive polymer resin (Note) Sooyang Chemtech, SY-CP-E421M) was mixed at a weight ratio of 40:60 to prepare a binder composition (6). The prepared binder composition (6) had a viscosity of 18.5 cps (25°C).

2) Preparation of water-based coating composition (6)

The water-based coating composition 6 was prepared by mixing 10% by weight of the prepared binder composition 6, 0.4% by weight of a wetting agent (ZonylFSH from DuPont), and 89.6% by weight of water. The viscosity of the prepared water-based coating composition (6) was 3.1cps (25°C).

3) Preparation of polyester film

A polyethylene terephthalate chip having a moisture content of 100 ppm or less was injected into a melt extruder, melted, and then extruded through a T-die, rapidly cooled and solidified with a casting drum having a surface temperature of 20°C to prepare a polyethylene terephthalate sheet having a thickness of 2000 µm. .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110° C., and then cooled to room temperature. Thereafter, the water-based coating composition 6 was coated on one side by a bar coating method, preheated at 140° C., dried, and stretched 3.5 times in the transverse direction (TD). Subsequently, heat treatment was performed at 235° C. in a 5-stage tenter, and heat-set at 200° C. by relaxing 10% in the machine direction and the transverse direction to prepare a 100 μm biaxially stretched film having an antistatic layer formed on one side. The thickness of the dry coating after stretching of the antistatic layer was 50 nm.

The physical properties of the film thus obtained are shown in Table 1 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Surface resistance before stretching (Ω/sq)
10V× 10s 5.19× 10 ⁶ 5.56×10 ⁶ 6.27× 10 ⁶ 7.52×10 ⁶ 7.54×10 ⁶ 6.84×10 ⁶ Surface resistance after stretching
(Ω/sq)
10V× 10s 1.74×10 ⁷ 1.24× 10 ⁷ 2.47×10 ⁷ 1.84×10 ⁷ 7.25×10 ⁷ 5.01×10 ⁷ Silicone adhesiveness (gf/inch) 1.5 1.7 2.5 2.9 1.2 1.4 Coating property before stretching ○ ○ ○ ○ ○ ○ Coating property after stretching ○ ○ ○ ○ ○ ○ Solvent resistance Isopropyl alcohol ◎ ◎ ◎ ◎ ○ ○ ethanol ◎ ◎ ◎ ◎ ○ ○ Methyl ethyl ketone ○ ◎ ○ ◎ × × toluene ○ ◎ ○ ◎ △ △ Ethyl acetate ○ ◎ ○ ◎ △ △

As shown in Table 1, it was confirmed that the polyester film of the present invention has not only excellent antistatic properties, but also improved surface resistance after stretching, excellent adhesion to silicone, and changes in physical properties of the coating layer before and after stretching. It was confirmed that it can be manufactured by in-line coating method due to the small number.

In addition, it was confirmed that the solvent resistance was greatly improved.

Claims (17)

A polyester film comprising a base layer made of a polyester resin and an antistatic layer laminated on one or both sides of the base layer,
The antistatic layer is formed by coating and drying an aqueous coating composition comprising a binder composition and water,
The binder composition includes a conductive polymer resin selected from polythiophene or polythiophene derivatives, and a water-dispersible polyester resin,
The water-dispersible polyester resin has a glass transition temperature of 110 to 120°C, an acid value of 5 mgKOH/g or less, a refractive index of 1.61 to 1.7, and a molecular weight of 26000 to 30000,
The antistatic layer is a polyester film having a sticking force of 1.5 to 3 gf/inch measured by laminating on a silicon layer and then standing for 30 minutes in an atmosphere having a temperature of 25°C and a humidity of 50%, and then performing a 180 degree peel test. According to claim 1,
The antistatic layer has a thickness of 0.03 to 0.05% of the total film thickness, and a polyester film having a surface resistance of 10 ⁵ to 10 ⁹ Ω/sq in the thickness range. delete According to claim 1,
The water-based coating composition is a polyester film using a viscosity of 2 ~ 5 cps (25 ℃). According to claim 1,
The binder composition is a polyester film that is 30 to 40% by weight of water-dispersible polyester resin, and 60 to 70% by weight of conductive polymer resin. The method of claim 5,
The binder composition is a polyester film further comprising 0.1 to 10% by weight of any one or more additives selected from pH adjusting agents, alcohol-based solvents, silicone-based or fluorine-based leveling agents. According to claim 1,
The water-based coating composition is a polyester film further comprising any one or two or more additives selected from a wetting agent, particles, slip agent, crosslinking agent, curing agent. According to claim 1,
The antistatic layer is a polyester film that is coated by an inline coating method. According to claim 1,
The antistatic layer is a polyester film having a dry coating thickness of 10 to 500 nm. According to claim 1,
The polyester film has a total thickness of 12 ~ 250㎛ polyester film. delete a) melt extrusion of the polyester resin to produce a polyester sheet;
b) stretching the polyester sheet in the machine direction;
c) an aqueous coating composition comprising a binder composition obtained by mixing a conductive polymer resin selected from polythiophene or a polythiophene derivative and a water-dispersible polyester resin and water on one or both sides of the polyester film stretched in the machine direction. After coating, stretching in the transverse direction; And
d) heat-setting the biaxially stretched polyester film;
Including,
As the water-dispersible polyester resin, a glass transition temperature of 110 to 120°C, an acid value of 5 mgKOH/g or less, a refractive index of 1.61 to 1.7, and a molecular weight of 26000 to 30000 are used.
The anti-static layer formed by coating the water-based coating composition was laminated to a silicon layer and left for 30 minutes in an atmosphere with a temperature of 25°C and a humidity of 50%. , Manufacturing method of polyester film. The method of claim 12,
The binder composition is a method for producing a polyester film, the water-dispersible polyester resin is 30 to 40% by weight, the conductive polymer resin is included in 60 to 70% by weight. The method of claim 13,
The binder composition is a method for producing a polyester film further comprising 0.1 to 10% by weight of any one or more additives selected from pH adjusting agents, alcohol-based solvents, silicone-based or fluorine-based leveling agents. The method of claim 14,
The water-based coating composition is a method of manufacturing a polyester film having a viscosity of 2 ~ 5 cps (25 ℃). The method of claim 12,
Stretching in the machine direction is stretched 3 to 4 times at 70 to 110℃,
The transverse stretching is a method of producing a polyester film that is stretched 3 to 4.5 times at 110 to 240°C. The method of claim 12,
The heat setting is a method of manufacturing a polyester film that is performed at 220 ~ 240 ℃.